When trying to compile either master or 1.0.4 on Funtoo Linux 1.4 with Linux kernel 5.6.3 (Gentoo kernel sources) and gcc 9.2.0 I get this issue:

$ make
make -C /lib64/modules/5.6.3-gentoo/build M=/home/mm/tools/akvcam/src  modules
make[1]: Entering directory '/usr/src/linux-5.6.3-gentoo'
  MODPOST 1 modules
ERROR: "video_device_release_empty" [/home/mm/tools/akvcam/src/akvcam.ko] undefined!
ERROR: "video_device_release" [/home/mm/tools/akvcam/src/akvcam.ko] undefined!
ERROR: "v4l2_device_unregister" [/home/mm/tools/akvcam/src/akvcam.ko] undefined!
ERROR: "__video_register_device" [/home/mm/tools/akvcam/src/akvcam.ko] undefined!
ERROR: "v4l2_device_register" [/home/mm/tools/akvcam/src/akvcam.ko] undefined!
ERROR: "video_device_alloc" [/home/mm/tools/akvcam/src/akvcam.ko] undefined!
ERROR: "video_unregister_device" [/home/mm/tools/akvcam/src/akvcam.ko] undefined!
make[2]: *** [scripts/Makefile.modpost:93: __modpost] Error 1
make[1]: *** [Makefile:1596: modules] Error 2
make[1]: Leaving directory '/usr/src/linux-5.6.3-gentoo'
make: *** [Makefile:42: all] Error 2

I've attached the kernel config as config.txt, since I suspect I may be missing some required setting.

Hello all,

I tried building and installing akvcam, but after the make install error i tried to run the command depmod -a and tried reinstalling as root, but with still no success.
`ricky@zorin-ricky:~/akvcam/src$ sudo make install
make -C /lib/modules/5.3.0-46-generic/build M=/home/ricky/akvcam/src modules_install
make[1]: ingresso nella directory "/usr/src/linux-headers-5.3.0-46-generic"
INSTALL /home/ricky/akvcam/src/akvcam.ko
At main.c:160:

• SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:72
• SSL error:2006D080:BIO routines:BIO_new_file:no such file: ../crypto/bio/bss_file.c:79
  sign-file: certs/signing_key.pem: No such file or directory
  DEPMOD 5.3.0-46-generic
  Warning: modules_install: missing 'System.map' file. Skipping depmod.
  make[1]: uscita dalla directory "/usr/src/linux-headers-5.3.0-46-generic"
  `
  what can i do?

I'm trying to use akvcam on pi.
build is ok (with some warnings), but if i call v4l2-compliance -d /dev/video1 -f i get kernel failures:

v4l2-compliance SHA   : not available

Driver Info:
	Driver name   : akvcam
	Card type     : Virtual Camera (output device)
	Bus info      : platform:akvcam-1
	Driver version: 4.9.80
	Capabilities  : 0x85200002
		Video Output
		Read/Write
		Streaming
		Extended Pix Format
		Device Capabilities
	Device Caps   : 0x05200002
		Video Output
		Read/Write
		Streaming
		Extended Pix Format

Compliance test for device /dev/video1 (not using libv4l2):

Required ioctls:
	test VIDIOC_QUERYCAP: OK

Allow for multiple opens:
	test second video open: OK
	test VIDIOC_QUERYCAP: OK
	test VIDIOC_G/S_PRIORITY: OK
	test for unlimited opens: OK

Debug ioctls:
	test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
	test VIDIOC_LOG_STATUS: OK (Not Supported)

Input ioctls:
	test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
	test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
	test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
	test VIDIOC_ENUMAUDIO: OK (Not Supported)
	test VIDIOC_G/S/ENUMINPUT: OK (Not Supported)
	test VIDIOC_G/S_AUDIO: OK (Not Supported)
	Inputs: 0 Audio Inputs: 0 Tuners: 0

Output ioctls:
	test VIDIOC_G/S_MODULATOR: OK (Not Supported)
	test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
	test VIDIOC_ENUMAUDOUT: OK (Not Supported)
	test VIDIOC_G/S/ENUMOUTPUT: OK
	test VIDIOC_G/S_AUDOUT: OK (Not Supported)
	Outputs: 1 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:
	test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
	test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
	test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
	test VIDIOC_G/S_EDID: OK (Not Supported)

Test output 0:

	Control ioctls:
		test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK (Not Supported)
		test VIDIOC_QUERYCTRL: OK (Not Supported)
		test VIDIOC_G/S_CTRL: OK (Not Supported)
		test VIDIOC_G/S/TRY_EXT_CTRLS: OK (Not Supported)
		test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK (Not Supported)
		test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
		Standard Controls: 0 Private Controls: 0

	Format ioctls:
		test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.421966] Internal error: Oops: 817 [#1] ARM

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.468172] Process v4l2-compliance (pid: 1736, stack limit = 0xcc708188)

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.470338] Stack: (0xcc709e70 to 0xcc70a000)

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.472746] 9e60:                                     be92fbc8 00000000 bf20d9ec 000000cc

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.476937] 9e80: cc3ace20 be92fbc8 d5239b00 bf20d9ec cc709ec4 cc709ea0 bf20ed54 bf20d9f8

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.482122] 9ea0: d50ffc00 ce237000 be92fbc8 c0cc5616 00000000 cc708000 cc709ed4 cc709ec8

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.486760] 9ec0: bf2100dc bf20ec6c cc709efc cc709ed8 bf09b66c bf2100b4 bf09b5b4 be92fbc8

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.492060] 9ee0: d520c2f8 ce237000 00000003 00000003 cc709f7c cc709f00 c0157a58 bf09b5c0

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.496519] 9f00: c092573c 00000001 ce2376e8 cc709f18 00000002 c0025cbc 00000000 00000000

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.501139] 9f20: 00000001 00000035 ce2376e0 00000002 00000000 d6f063c0 ce2376e8 00000000

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.506295] 9f40: cc709f7c cc709f50 c014599c c0188068 00000000 ce237000 be92fbc8 ce237000

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.511857] 9f60: c0cc5616 00000003 cc708000 00000000 cc709fa4 cc709f80 c01581d4 c01579c8

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.517691] 9f80: be92fbb8 0005ce50 be930354 00000002 00000036 c000ffc4 00000000 cc709fa8

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.524502] 9fa0: c000fe40 c015819c 0005ce50 be930354 00000003 c0cc5616 be92fbc8 be92fbb8

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.529875] 9fc0: 0005ce50 be930354 00000002 00000036 00000001 be93050c 0005d268 be92fd4c

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.535299] 9fe0: 0005d088 be92fb9c 00018300 b6b7080c 20000010 00000003 86868686 86868686

Message from syslogd@raspberrypi at Dec 26 12:25:55 ...
 kernel:[ 3493.582511] Code: ba00001d e3530002 b4c02001 d4c02001 (e4c02001)
Speicherzugriffsfehler

I build like it's decribed on wiki and use the same config to test it.
Pi has kernel 4.9.80.

`
$ make
make -C /lib/modules/4.18.0-11-generic/build M=/home/fcuenca/Descargas/akvcam-master/src modules
make[1]: se entra en el directorio '/usr/src/linux-headers-4.18.0-11-generic'
CC [M] /home/fcuenca/Descargas/akvcam-master/src/module.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/attributes.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/buffer.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/buffers.o
symbolmap: la: invalid section
CC [M] /home/fcuenca/Descargas/akvcam-master/src/controls.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/device.o
symbolmap: la: invalid section
CC [M] /home/fcuenca/Descargas/akvcam-master/src/driver.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/events.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/file_read.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/format.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/frame.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/global_deleter.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/ioctl.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/list.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/log.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/map.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/mmap.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/node.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/object.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/rbuffer.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/settings.o
CC [M] /home/fcuenca/Descargas/akvcam-master/src/utils.o
LD [M] /home/fcuenca/Descargas/akvcam-master/src/akvcam.o
Building modules, stage 2.
MODPOST 1 modules
CC /home/fcuenca/Descargas/akvcam-master/src/akvcam.mod.o
LD [M] /home/fcuenca/Descargas/akvcam-master/src/akvcam.ko
make[1]: se sale del directorio '/usr/src/linux-headers-4.18.0-11-generic'

$ sudo make install
make -C /lib/modules/4.18.0-11-generic/build M= modules_install
make[1]: se entra en el directorio '/usr/src/linux-headers-4.18.0-11-generic'
cp: no se puede efectuar stat' sobre './modules.order': No existe el archivo o el directorio make[1]: *** [Makefile:1278: _modinst_] Error 1 make[1]: se sale del directorio '/usr/src/linux-headers-4.18.0-11-generic' make: *** [Makefile:47: install] Error 2

After downloading and running the installer attached, I couldn't find the akvcam anywhere on my computer. I search by using a camera app to try to find a camera device, it didn't work. Same thing happened when I tried to search for it using discord.

I've got a dvcam connected on /dev/fw0
I can see it on vlc using vlc -vvv dv/rawdv:///dev/fw0 - but of course zoom etc can't see it

Now I'm scratching my head as to how to connect a cam to akvcam? Is this even possible?

Thanks

make -C /lib/modules/5.3.0-28-generic/build M=/home/jeff/Downloads/akvcam-master/src modules_install
make[1]: Entering directory '/usr/src/linux-headers-5.3.0-28-generic'
INSTALL /home/jeff/Downloads/akvcam-master/src/akvcam.ko
At main.c:160:

• SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:72
• SSL error:2006D080:BIO routines:BIO_new_file:no such file: ../crypto/bio/bss_file.c:79
  sign-file: certs/signing_key.pem: No such file or directory
  DEPMOD 5.3.0-28-generic
  Warning: modules_install: missing 'System.map' file. Skipping depmod.
  make[1]: Leaving directory '/usr/src/linux-headers-5.3.0-28-generic'

I installed libelf-dev and using sudo depmod -a doen't make a difference, still get the same results

Hi,

I've been playing around with akvcam to do some screen capturing and ran into the problem that it only works once.
With ffmpeg is do the screen grabbing:
ffmpeg -f x11grab -r 20 -s 640x480 -i :0.0+0,200 -f v4l2 -vcodec rawvideo -pix_fmt rgb24 /dev/video0

and I can have a look at with:
ffplay /dev/video1

This works perfect. If I stop both and try to do it again. The ffplay command gives me the error:
/dev/video1: Device or resource busy.

From the wiki checking compliance, checking properties, and cat and echo all work fine even after the device or resource busy error.

Also other programs accessing the virtual cam give errors that they can not use the device. If I restart my computer it works again.

Any idea what is going on?

Cheers, Rico

This is what I do:

• install driver using DKMS method (everything goes well)
• start ./webcamoid-8.7.1-x86_64.AppImage
• create output device
• start Teams and select the previously created video device
• I can see the video in a preview from the webcamoid device but the driver crashes
• I am not able to see video stream from the webcamoid virtual device anymore

Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477009] ------------[ cut here ]------------
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477013] Unknown pixelformat 0x00000000
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477048] WARNING: CPU: 1 PID: 32211 at /build/linux-UDHJtG/linux-4.15.0/drivers/media/v4l2-core/v4l2-ioctl.c:1293 v4l_fill_fmtdesc+0xf4d/0x1260 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477050] Modules linked in: akvcam(OE) ccm rfcomm vboxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) bnep hid_multitouch intel_rapl x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm irqbypass snd_soc_skl snd_soc_skl_ipc snd_hda_codec_hdmi intel_cstate snd_hda_ext_core snd_soc_sst_dsp intel_rapl_perf nls_iso8859_1 snd_soc_sst_ipc arc4 snd_soc_acpi snd_soc_core snd_hda_codec_realtek snd_compress hp_wmi ac97_bus snd_hda_codec_generic sparse_keymap serio_raw wmi_bmof snd_pcm_dmaengine snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep uvcvideo snd_pcm videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 snd_seq_midi snd_seq_midi_event snd_rawmidi videobuf2_core btusb joydev btrtl snd_seq btbcm videodev btintel iwlmvm bluetooth snd_seq_device media snd_timer input_leds snd mac80211 ecdh_generic soundcore
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477078] shpchp iwlwifi ucsi_acpi typec_ucsi typec cfg80211 idma64 int3403_thermal virt_dma mei_me processor_thermal_device int340x_thermal_zone hp_accel mei intel_lpss_pci intel_soc_dts_iosf lis3lv02d mac_hid input_polldev acpi_pad intel_lpss intel_pch_thermal hp_wireless int3400_thermal acpi_thermal_rel sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 btrfs xor zstd_compress raid6_pq algif_skcipher af_alg hid_logitech_hidpp hid_logitech_dj hid_generic usbhid dm_crypt dm_mirror dm_region_hash dm_log crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel i915 aes_x86_64 crypto_simd glue_helper cryptd i2c_algo_bit drm_kms_helper nvme psmouse nvme_core syscopyarea sysfillrect sysimgblt ahci fb_sys_fops r8169 sdhci_pci drm libahci i2c_hid mii sdhci hid wmi video [last unloaded: akvcam]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477114] CPU: 1 PID: 32211 Comm: AudioThread Tainted: G D W OE 4.15.0-96-generic #97-Ubuntu
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477115] Hardware name: HP HP ProBook 440 G6/8537, BIOS R71 Ver. 01.08.03 07/17/2019
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477124] RIP: 0010:v4l_fill_fmtdesc+0xf4d/0x1260 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477126] RSP: 0018:ffffafcf82a9fc30 EFLAGS: 00010282
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477128] RAX: 0000000000000000 RBX: ffffafcf82a9fd68 RCX: 0000000000000006
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477129] RDX: 0000000000000007 RSI: 0000000000000092 RDI: ffff9850e7456490
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477131] RBP: ffffafcf82a9fc40 R08: 0000000000001298 R09: 000000000000000f
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477132] R10: ffff984f9efe7b40 R11: ffffffff9b15c80d R12: ffff985008e8bc00
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477133] R13: ffffffffc0e38860 R14: ffff984f9efe7b40 R15: ffff985008e8bc00
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477135] FS: 00007f3e71ffb700(0000) GS:ffff9850e7440000(0000) knlGS:0000000000000000
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477137] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477138] CR2: 00007f3e5800ad98 CR3: 00000003498e2005 CR4: 00000000003606e0
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477140] Call Trace:
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477149] v4l_enum_fmt+0x7d/0x130 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477155] __video_do_ioctl+0x370/0x380 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477159] ? terminate_walk+0x90/0x100
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477166] video_usercopy+0x24d/0x640 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477170] ? video_ioctl2+0x20/0x20 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477175] video_ioctl2+0x15/0x20 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477179] v4l2_ioctl+0xc8/0xf0 [videodev]
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477181] do_vfs_ioctl+0xa8/0x630
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477183] ? putname+0x4c/0x60
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477185] ? do_sys_open+0x13d/0x2c0
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477187] SyS_ioctl+0x79/0x90
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477190] do_syscall_64+0x73/0x130
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477193] entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477195] RIP: 0033:0x7f3ecd5845d7
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477196] RSP: 002b:00007f3e71ffa508 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477198] RAX: ffffffffffffffda RBX: 00007f3e580054f0 RCX: 00007f3ecd5845d7
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477199] RDX: 00007f3e71ffa530 RSI: ffffffffc0405602 RDI: 000000000000009c
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477200] RBP: 00007f3e71ffa5a0 R08: 0000000000000004 R09: 0000000000000000
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477201] R10: 00007f3e580008d0 R11: 0000000000000246 R12: 00007f3e71ffa530
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477202] R13: 00007f3e71ffa518 R14: 000000000000009c R15: 0000555a252215f0
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477204] Code: 30 0f 84 b4 01 00 00 3d 4a 4c 32 30 0f 84 97 01 00 00 3d 4d 33 31 30 0f 84 7a 01 00 00 89 c6 48 c7 c7 f7 de dd c0 e8 e3 5d ac d8 <0f> 0b 80 7b 0c 00 0f 85 d6 f3 ff ff 8b 43 2c 48 c7 c1 9e d2 dd
Apr 17 10:34:56 HP-ProBook-440-G6 kernel: [ 5426.477218] ---[ end trace 6e11abb96fc5a0b1 ]---

Is there any way to programmatically create and remove virtual webcams on demand?

after compiling latest version, using the example config file, loading the module and running the following:
sudo ffmpeg -i /dev/video0 -f v4l2 /dev/video7

/dev/video2 output was weird, like this:

Then a few seconds later I got kernel panic:

Jan 23 15:56:40 laptop kernel: [ 4311.764840] ------------[ cut here ]------------
Jan 23 15:56:40 laptop kernel: [ 4311.764843] refcount_t: underflow; use-after-free.
Jan 23 15:56:40 laptop kernel: [ 4311.764879] WARNING: CPU: 6 PID: 23877 at lib/refcount.c:28 refcount_warn_saturate+0xae/0xf0
Jan 23 15:56:40 laptop kernel: [ 4311.764880] Modules linked in: akvcam(OE) thunderbolt rfcomm nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_masq xt_conntrack nft_ct xt_MASQUERADE nf_conntr
ack_netlink xfrm_user xfrm_algo xt_addrtype iptable_filter iptable_nat bpfilter br_netfilter nft_chain_nat bridge nf_nat stp nf_conntrack llc nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c nf_tables nfnetlink vb
oxnetadp(OE) vboxnetflt(OE) vboxdrv(OE) ccm aufs cmac algif_hash algif_skcipher af_alg overlay bnep nls_iso8859_1 intel_rapl_msr nvidia_uvm(O) mei_hdcp intel_rapl_common x86_pkg_temp_thermal nvidia_drm(PO
) intel_powerclamp nvidia_modeset(PO) coretemp kvm_intel kvm nvidia(PO) intel_cstate snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi uvcvideo snd_hda_intel videobuf2_vmalloc s
nd_intel_dspcfg videobuf2_memops videobuf2_v4l2 snd_hda_codec videobuf2_common snd_hda_core videodev btusb snd_hwdep btrtl btbcm mc btintel snd_pcm bluetooth snd_seq_midi snd_seq_midi_event ecdh_generic e
cc snd_rawmidi
Jan 23 15:56:40 laptop kernel: [ 4311.764965]  iwlmvm snd_seq mac80211 input_leds joydev libarc4 snd_seq_device snd_timer serio_raw intel_wmi_thunderbolt intel_rapl_perf iwlwifi wmi_bmof snd cfg80211 ipmi
_devintf ipmi_msghandler mei_me soundcore mei intel_pch_thermal ideapad_laptop sparse_keymap mac_hid acpi_pad sch_fq_codel parport_pc ppdev lp parport ip_tables x_tables autofs4 dm_crypt hid_logitech_hidp
p hid_logitech_dj usbhid hid_generic i915 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel i2c_algo_bit aesni_intel drm_kms_helper crypto_simd cryptd glue_helper syscopyarea sysfillrect sysimgblt fb_sys_
fops psmouse cec rc_core nvme intel_lpss_pci drm i2c_i801 intel_lpss nvme_core r8169 ahci idma64 realtek libahci virt_dma i2c_hid hid wmi video pinctrl_sunrisepoint pinctrl_intel
Jan 23 15:56:40 laptop kernel: [ 4311.765047] CPU: 6 PID: 23877 Comm: akvcam-thread-3 Tainted: P           OE     5.6.0-1026-oem #26-Ubuntu
Jan 23 15:56:40 laptop kernel: [ 4311.765050] Hardware name: LENOVO INVA/LNVNB161216, BIOS 4GCN38WW 07/18/2018
Jan 23 15:56:40 laptop kernel: [ 4311.765058] RIP: 0010:refcount_warn_saturate+0xae/0xf0
Jan 23 15:56:40 laptop kernel: [ 4311.765064] Code: 7b 31 2e 01 01 e8 77 22 b5 ff 0f 0b 5d c3 80 3d 68 31 2e 01 00 75 91 48 c7 c7 a0 8e 9e bc c6 05 58 31 2e 01 01 e8 57 22 b5 ff <0f> 0b 5d c3 80 3d 46 31 
2e 01 00 0f 85 6d ff ff ff 48 c7 c7 f8 8e
Jan 23 15:56:40 laptop kernel: [ 4311.765067] RSP: 0018:ffffb40b46fcfe48 EFLAGS: 00010286
Jan 23 15:56:40 laptop kernel: [ 4311.765071] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000007
Jan 23 15:56:40 laptop kernel: [ 4311.765074] RDX: 0000000000000007 RSI: 0000000000000082 RDI: ffff8e7f9ed99800
Jan 23 15:56:40 laptop kernel: [ 4311.765077] RBP: ffffb40b46fcfe48 R08: 00000000000006fc R09: 0000000000000004
Jan 23 15:56:40 laptop kernel: [ 4311.765080] R10: 0000000000000000 R11: 0000000000000001 R12: ffff8e7e337a2bc0
Jan 23 15:56:40 laptop kernel: [ 4311.765082] R13: 0000000000000000 R14: ffff8e7daf811600 R15: ffffb40b46e7fc40
Jan 23 15:56:40 laptop kernel: [ 4311.765086] FS:  0000000000000000(0000) GS:ffff8e7f9ed80000(0000) knlGS:0000000000000000
Jan 23 15:56:40 laptop kernel: [ 4311.765089] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Jan 23 15:56:40 laptop kernel: [ 4311.765092] CR2: 00007f0408100188 CR3: 00000001f660a002 CR4: 00000000003606e0
Jan 23 15:56:40 laptop kernel: [ 4311.765095] Call Trace:
Jan 23 15:56:40 laptop kernel: [ 4311.765130]  akvcam_frame_delete.part.0+0x52/0x60 [akvcam]
Jan 23 15:56:40 laptop kernel: [ 4311.765148]  akvcam_frame_delete+0x13/0x20 [akvcam]
Jan 23 15:56:40 laptop kernel: [ 4311.765162]  akvcam_default_frame.part.0+0x3e/0xd0 [akvcam]
Jan 23 15:56:40 laptop kernel: [ 4311.765177]  akvcam_device_clock_run_once+0x1e3/0x260 [akvcam]
Jan 23 15:56:40 laptop kernel: [ 4311.765191]  akvcam_device_clock_timeout+0x3d/0x60 [akvcam]
Jan 23 15:56:40 laptop kernel: [ 4311.765199]  kthread+0x104/0x140
Jan 23 15:56:40 laptop kernel: [ 4311.765212]  ? akvcam_device_clock_run_once+0x260/0x260 [akvcam]
Jan 23 15:56:40 laptop kernel: [ 4311.765218]  ? kthread_park+0x90/0x90
Jan 23 15:56:40 laptop kernel: [ 4311.765227]  ret_from_fork+0x35/0x40
Jan 23 15:56:40 laptop kernel: [ 4311.765234] ---[ end trace 24815edb4fa9ce14 ]---

Linux laptop 5.6.0-1026-oem #26-Ubuntu SMP Sun Sep 6 11:06:50 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Ubuntu 20.04.1 LTS x86_64

Sytem freeze on Debian

Note

Happy to provide other information if required.

Steps to reproduce

• Version: Using 1.2.0 or master branch (2020-01-23)

Running any of the execution commands specified below will lead to a complete system freeze. This does not happen at the first run, but around the 4th (give or take) run.

During the system freeze my screen is still visible (but frozen). If I happen to have e.g. youtube running in the background with sound, I can hear the sound to continue for around 10sec, until it also stops. Only thing I can do from this moment on, is to power off my computer via the power button.

Execution

webm

ffmpeg -i test.webm -s 1280x720 -r 30 -f v4l2 -vcodec rawvideo -pix_fmt rgb24 /dev/video7

  Metadata:
    encoder         : GStreamer matroskamux version 1.14.4
    creation_time   : 2021-01-20T18:00:18.000000Z
  Duration: 00:00:01.92, start: 0.000000, bitrate: 1908 kb/s
    Stream #0:0(eng): Video: vp8, yuv420p(progressive), 960x540, SAR 1:1 DAR 16:9, 15 fps, 15 tbr, 1k tbn, 1k tbc (default)
    Metadata:
      title           : Video
    Stream #0:1(eng): Audio: vorbis, 44100 Hz, mono, fltp (default)
    Metadata:
      title           : Audio

mp4

ffmpeg -i test.mp4 -s 1280x720 -r 30 -f v4l2 -vcodec rawvideo -pix_fmt rgb24 /dev/video7

  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:00:01.93, start: 0.000000, bitrate: 1943 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 960x540 [SAR 1:1 DAR 16:9], 1846 kb/s, 15 fps, 15 tbr, 15360 tbn, 30 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 92 kb/s (default)
    Metadata:
      handler_name    : SoundHandler

System information

$ uname
4.19.0-13-amd64 #1 SMP Debian 4.19.160-2 (2020-11-28) x86_64 GNU/Linux

config.ini

[Cameras]
cameras/size = 2

cameras/1/type = output
cameras/1/mode = mmap, userptr, rw
cameras/1/description = Virtual Camera (output device)
cameras/1/formats = 2
cameras/1/videonr = 7

cameras/2/type = capture
cameras/2/mode = mmap, userptr, rw
cameras/2/description = Virtual Camera (capture device)
cameras/2/formats = 2, 3
cameras/2/videonr = 9


[Formats]
formats/size = 3

formats/1/format = RGB24, YUY2
formats/1/width = 1280
formats/1/height = 720
formats/1/fps = 30/1, 15/1, 15/2

formats/2/format = RGB24
formats/2/width = 640
formats/2/height = 480
formats/2/fps = 30/1, 15/1, 15/2

formats/3/format = RGB24
formats/3/width = 1280
formats/3/height = 720
formats/3/fps = 30/1, 15/1, 15/2


[Connections]
connections/size = 1
connections/1/connection = 1:2

I'm having the exact same issue as this person on the AUR; I'll add that I was able to build v4l2loopback-dkms-git, but not v4l2loopback-dkms

https://pastebin.com/zY0KD9am
https://aur.archlinux.org/packages/akvcam-dkms/#comment-737888

Hi,

I was able to install akvcam-dkms 1.0.3-1 under kernel 5.5.13-arch2-1. However, both akvcam-dkms and akvcam-dkms-git fail to build under 5.6.2.arch1-2. Error output:

/home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.c: In function ‘akvcam_buffers_dequeue’: /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.c:488:30: error: passing argument 1 of ‘akvcam_get_timestamp’ from incompatible pointer type [-Werror=incompatible-pointer-types] 488 | akvcam_get_timestamp(&v4l2_buff->timestamp); | ^~~~~~~~~~~~~~~~~~~~~ | | | struct __kernel_v4l2_timeval * In file included from /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.h:28, from /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.c:28: /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/utils.h:101:43: note: expected ‘struct timeval ’ but argument is of type ‘struct __kernel_v4l2_timeval ’ 101 | void akvcam_get_timestamp(struct timeval tv); | ~~~~~~~~~~~~~~~~^~ /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.c: In function ‘akvcam_buffers_write_frame’: /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.c:729:34: error: passing argument 1 of ‘akvcam_get_timestamp’ from incompatible pointer type [-Werror=incompatible-pointer-types] 729 | akvcam_get_timestamp(&v4l2_buff->timestamp); | ^~~~~~~~~~~~~~~~~~~~~ | | | struct __kernel_v4l2_timeval * In file included from /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.h:28, from /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.c:28: /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/utils.h:101:43: note: expected ‘struct timeval ’ but argument is of type ‘struct __kernel_v4l2_timeval ’ 101 | void akvcam_get_timestamp(struct timeval tv); | ~~~~~~~~~~~~~~~~^~ cc1: some warnings being treated as errors make[2]: *** [scripts/Makefile.build:268: /home/blah/.cache/yay/akvcam-dkms-git/src/akvcam/src/buffers.o] Error 1

Something changed in the kernel code related to struct timeval? I haven't tried to figure out the details of what's gone wrong.

The example akvcam configuration file (https://github.com/webcamoid/akvcam/blob/master/share/config_example.ini) is not very capable, the one generated by webcamoid 8.5.0 (the one that's in my repository) supports way more format. So I think example config_example.ini should be replaced by the one that's generated by webcamoid.

Hi all,

First, thanks for the great work you did!!

I followed the wiki for building and installing akvcam and I got it to work. All your examples worked. Also set the module to load on boot. But now it doesn't work anymore. Checking compliance and properties works, both give no errors. The cat and echo example goes wrong.

cat /dev/urandom > /dev/video1 gives:
cat: write error: Invalid argument

I enabled rw mode in both the capture device and output device.

I'am on Ubuntu 18.04.4.
My lsmod | grep videodev output:

videodev              184320  4 videobuf2_core,videobuf2_v4l2,uvcvideo,akvcam
media                  40960  2 videodev,uvcvideo

dmesg | grep akvcam output:

[    7.560406] akvcam: loading out-of-tree module taints kernel.
[    7.560448] akvcam: module verification failed: signature and/or required key missing - tainting kernel

Can you help me with this?

Cheers, Rico

provide a docker way of using this tool

• docker image
• input video source, say, input.mp4
• virtual device, say, /dev/video9

akvcam module fails with kernel 5.7
v4l2 API have some changes (VFL_TYPE_GRABBER => VFL_TYPE_VIDEO)
here a patch to solve it
akvcam.zip

darkonen

~/akvcam/src$ make
make -C /lib/modules/5.4.0-1029-aws/build M=/home/ubuntu/akvcam/src modules
make[1]: Entering directory '/usr/src/linux-headers-5.4.0-1029-aws'
CC [M] /home/ubuntu/akvcam/src/module.o
CC [M] /home/ubuntu/akvcam/src/attributes.o
CC [M] /home/ubuntu/akvcam/src/buffer.o
CC [M] /home/ubuntu/akvcam/src/buffers.o
CC [M] /home/ubuntu/akvcam/src/controls.o
CC [M] /home/ubuntu/akvcam/src/device.o
CC [M] /home/ubuntu/akvcam/src/driver.o
CC [M] /home/ubuntu/akvcam/src/events.o
CC [M] /home/ubuntu/akvcam/src/file_read.o
CC [M] /home/ubuntu/akvcam/src/format.o
CC [M] /home/ubuntu/akvcam/src/frame.o
CC [M] /home/ubuntu/akvcam/src/global_deleter.o
CC [M] /home/ubuntu/akvcam/src/ioctl.o
CC [M] /home/ubuntu/akvcam/src/list.o
CC [M] /home/ubuntu/akvcam/src/log.o
CC [M] /home/ubuntu/akvcam/src/map.o
CC [M] /home/ubuntu/akvcam/src/mmap.o
CC [M] /home/ubuntu/akvcam/src/node.o
CC [M] /home/ubuntu/akvcam/src/object.o
CC [M] /home/ubuntu/akvcam/src/rbuffer.o
CC [M] /home/ubuntu/akvcam/src/settings.o
CC [M] /home/ubuntu/akvcam/src/utils.o
LD [M] /home/ubuntu/akvcam/src/akvcam.o
Building modules, stage 2.
MODPOST 1 modules
ERROR: "video_device_release_empty" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "video_device_release" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "v4l2_device_unregister" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "__video_register_device" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "v4l2_device_register" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "video_device_alloc" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "video_unregister_device" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
scripts/Makefile.modpost:93: recipe for target '__modpost' failed
make[2]: *** [__modpost] Error 1
Makefile:1670: recipe for target 'modules' failed
make[1]: *** [modules] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.4.0-1029-aws'
Makefile:42: recipe for target 'all' failed
make: *** [all] Error 2

Might be a total noob issue but make produces this for me..

make -C /lib/modules/4.15.0-48-generic/build M=/home/nooitaf/repos/akvcam/src  modules
make[1]: Entering directory '/usr/src/linux-headers-4.15.0-48-generic'
arch/x86/Makefile:245: *** You are building kernel with non-retpoline compiler, please update your compiler..  Stop.
make[1]: Leaving directory '/usr/src/linux-headers-4.15.0-48-generic'
make: *** [Makefile:42: all] Error 2

$ gcc -v
gcc version 5.5.0 (Homebrew gcc 5.5.0_4) 

$ uname -a
Linux nooitbox 4.15.0-48-generic #51~16.04.1-Ubuntu SMP Fri Apr 5 12:01:12 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

I ran into this problem while running make install:

$ sudo make install
make -C /usr/lib/modules/5.4.0-21-generic/build M=/home/bryan/git/webcamoid/akvcam/src modules_install
make[1]: Entering directory '/usr/src/linux-headers-5.4.0-21-generic'
  INSTALL /home/bryan/git/webcamoid/akvcam/src/akvcam.ko
At main.c:160:
- SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:69
- SSL error:2006D080:BIO routines:BIO_new_file:no such file: ../crypto/bio/bss_file.c:76
sign-file: certs/signing_key.pem: No such file or directory
  DEPMOD  5.4.0-21-generic
Warning: modules_install: missing 'System.map' file. Skipping depmod.
make[1]: Leaving directory '/usr/src/linux-headers-5.4.0-21-generic'

Using Fedora 30 on 5.1.8-300.fc30.x86_64.

I have tested considerably with VLC, ffplay, Webcamoid, etc. All non-browser apps pick up /dev/video1 absolutely perfectly and display the content correctly and without corruption.

The issue for me is using either the Firefox or Chrome (+ Chromium) web browsers.

The Chrome-based browsers detect the /dev/video1 camera and display the video at the approximately correct frame rate. However, the content is horribly distorted into various shades of pink and the video is rendered multiple times.

The Firefox browser also detects the /dev/video1 camera but in all test cases (different websites demanding webcam) it seems it attempts to "load" it but it just doesn't ever complete. The image on screen will remain as default and no content is ever rendered.

The method of transmission to video1 is as follows:

ffmpeg -i myVideo.mp4 -s 640x480 -r 30 -f v4l2 -vcodec rawvideo -pix_fmt rgb24 /dev/video0

Please do let me know which logs would be useful and I'll attempt to provide.

Hi,
Thanks for all your hard work. I'm a little confused by the documentation here

https://github.com/webcamoid/akvcam/wiki/Configure-the-cameras

which states

An Output device can be connected to many Capture devices, but only one Output device can be connected to a Capture device.

i'm not sure if i'm just being thick but i can't see the difference between these two contradictory sentences.

archlinux :
kernel 5.0:

make -C /usr/lib/modules/5.0.0-arch1-1-ARCH/build M=/tmp/src modules
make[1]: Entering directory '/usr/lib/modules/5.0.0-arch1-1-ARCH/build'
CC [M] /tmp/src/module.o
CC [M] /tmp/src/attributes.o
CC [M] /tmp/src/buffer.o
CC [M] /tmp/src/buffers.o
/tmp/src/buffers.c: In function ‘akvcam_buffers_dequeue’:
/tmp/src/buffers.c:488:9: error: implicit declaration of function ‘do_gettimeofday’; did you mean ‘do_settimeofday64’? [-Werror=implicit-function-declaration]
do_gettimeofday(&v4l2_buff->timestamp);
^~~~~~~~~~~~~~~
do_settimeofday64
cc1: some warnings being treated as errors
make[2]: *** [scripts/Makefile.build:277: /tmp/src/buffers.o] Error 1
make[1]: *** [Makefile:1553: module/tmp/src] Error 2
make[1]: Leaving directory '/usr/lib/modules/5.0.0-arch1-1-ARCH/build'
make: *** [Makefile:42: all] Error 2

sudo chown -vf 600 /etc/akvcam/config.ini

should probably be

sudo chmod -vf 600 /etc/akvcam/config.ini

$ make
make -C /lib/modules/4.15.0-46-generic/build M=/home/akvcam-master/src modules
make[1]: se entra en el directorio '/usr/src/linux-headers-4.15.0-46-generic'
Makefile:975: "Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel"
CC [M] /home/akvcam-master/src/module.o
CC [M] /home/akvcam-master/src/attributes.o
CC [M] /home/akvcam-master/src/buffer.o
CC [M] /home/akvcam-master/src/buffers.o
symbolmap: la: invalid section
CC [M] /home/akvcam-master/src/controls.o
CC [M] /home/akvcam-master/src/device.o
symbolmap: la: invalid section
CC [M] /home/akvcam-master/src/driver.o
CC [M] /home/akvcam-master/src/events.o
CC [M] /home/akvcam-master/src/file_read.o
CC [M] /home/akvcam-master/src/format.o
CC [M] /home/akvcam-master/src/frame.o
CC [M] /home/akvcam-master/src/global_deleter.o
CC [M] /home/akvcam-master/src/ioctl.o
CC [M] /home/akvcam-master/src/list.o
CC [M] /home/akvcam-master/src/log.o
CC [M] /home/akvcam-master/src/map.o
CC [M] /home/akvcam-master/src/mmap.o
CC [M] /home/akvcam-master/src/node.o
CC [M] /home/akvcam-master/src/object.o
CC [M] /home/akvcam-master/src/rbuffer.o
CC [M] /home/akvcam-master/src/settings.o
CC [M] /home/akvcam-master/src/utils.o
LD [M] /home/akvcam-master/src/akvcam.o
Building modules, stage 2.
MODPOST 1 modules
CC /home/akvcam-master/src/akvcam.mod.o
LD [M] /home/akvcam-master/src/akvcam.ko
make[1]: se sale del directorio '/usr/src/linux-headers-4.15.0-46-generic'

$ sudo make install
[sudo] contraseña para ad:
make -C /lib/modules/4.15.0-46-generic/build M=/home/akvcam-master/src modules_install
make[1]: se entra en el directorio '/usr/src/linux-headers-4.15.0-46-generic'
Makefile:975: "Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel"
INSTALL /home/akvcam-master/src/akvcam.ko
At main.c:160:

• SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:74
• SSL error:2006D080:BIO routines:BIO_new_file:no such file: ../crypto/bio/bss_file.c:81
  sign-file: certs/signing_key.pem: No such file or directory
  DEPMOD 4.15.0-46-generic
  make[1]: se sale del directorio '/usr/src/linux-headers-4.15.0-46-generic'

hello, i installed akvcam 1.1.1 using the prepackaged installer akvcam-installer-1.1.1.run and now i seem to be going round in circles trying to activate the module, it's all very unfamilliar to me. got through creating the files in /etc/akvcam/ but still having problems like the .ko not being recognised, not understanding what dkms is supposed to be doing .. basicaly having it installed like that didn't help me understand what it was doing and what still needed to be done.
so i think it's time to remove it all and try again .. but there's no indication of how to uninstall, or where to find each of the files the installer created and what options and configurations it may have modified.
please could anyone help with uninstalling and perhaps even explain why each bit goes where it does?

Hey, it's me again. I installed Webcamoid without any problems but wanted to install akvcam to use webcamoid as a virtual camera on zoom (custom filters and all). I tried installing akvcam but every time I try it does not show up after running this command ls /lib/modules/$(uname -r)/extra/akvcam.ko*. I even checked the folder manually and the driver is not there. I installed akvcam inside this directory: /home/user/Webcamoid/akvcam then used the make and make install which seemed to run successfully, but it still does not show up. Any solution to this?

Appears that there is an issue with using gst-launch with akvcam virtual device, as it throws the following, even with the example commands from the wiki:

user@laptop:~$ gst-launch-1.0 -v videotestsrc ! v4l2sink device=/dev/video5
Setting pipeline to PAUSED ...
ERROR: Pipeline doesn't want to pause.
ERROR: from element /GstPipeline:pipeline0/GstV4l2Sink:v4l2sink0: Device '/dev/video5' is not a output device.
Additional debug info:
v4l2_calls.c(636): gst_v4l2_open (): /GstPipeline:pipeline0/GstV4l2Sink:v4l2sink0:
Capabilities: 0x5200001
Setting pipeline to NULL ...
Freeing pipeline ...

Device works fine with webcamoid, just not for anything else...

Here's the log:

------------[ cut here ]------------
kernel BUG at mm/slub.c:4113!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
CPU: 13 PID: 2556 Comm: libobs: graphic Tainted: P           OE     5.9.10-zen1-1-zen #1
Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X570 Phantom Gaming 4, BIOS P1.60 08/21/2019
RIP: 0010:kfree+0x3a2/0x450
Code: 90 fd ff ff 48 8b 45 00 45 31 e4 a9 00 00 01 00 74 05 44 0f b6 65 51 48 8b 45 00 a9 00 00 01 00 75 0a 48 8b 45 08 a8 01 75 02 <0f> 0b 48 8b 45 00 44>
RSP: 0018:ffffba5a8aaffe30 EFLAGS: 00010246
RAX: ffffe4160c36f748 RBX: ffff9b8200000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: ffff9b8200000000
RBP: ffffe4160c000000 R08: ffff9b828a4f882c R09: ffff9b838a4f880b
R10: ffffffffffffffff R11: 0000000050424752 R12: 0000000000000000
R13: ffff9b81fe46d120 R14: 0000000000000000 R15: 0000000000000040
FS:  00007f5fe1b93640(0000) GS:ffff9b830eb40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f60082cf000 CR3: 000000038f208000 CR4: 00000000003506e0
Call Trace:
 ? snprintf+0x51/0x70
 akvcam_list_delete+0x86/0xd0 [akvcam]
 akvcam_ioctl_enum_fmt+0xcb/0x130 [akvcam]
 ? akvcam_ioctl_s_output+0x80/0x80 [akvcam]
 akvcam_ioctl_do+0xa9/0x170 [akvcam]
 akvcam_node_ioctl+0x22/0x30 [akvcam]
 v4l2_ioctl+0x48/0x50 [videodev]
 __x64_sys_ioctl+0x83/0xb0
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f60127dbd5d
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73>
RSP: 002b:00007f5fe1b921a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5fe0050280 RCX: 00007f60127dbd5d
RDX: 00007f5fe1b92210 RSI: 00000000c0405602 RDI: 0000000000000030
RBP: 00007f5fe1b921e0 R08: 00007f5fe1b92430 R09: 00007f5fe1b92430
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000000001
R13: 0000000000000009 R14: 00007f5fe1b92210 R15: 00007f5fd41acb30
Modules linked in: akvcam(OE) fuse wireguard curve25519_x86_64 libchacha20poly1305 chacha_x86_64 poly1305_x86_64 libblake2s blake2s_x86_64 ip6_udp_tunnel >
 i2c_algo_bit dca wmi pinctrl_amd acpi_cpufreq evdev joydev input_leds mac_hid nfsd vboxnetflt(OE) vboxnetadp(OE) auth_rpcgss nfs_acl lockd vboxdrv(OE) gr>
---[ end trace 047a5b141a572126 ]---
RIP: 0010:kfree+0x3a2/0x450
Code: 90 fd ff ff 48 8b 45 00 45 31 e4 a9 00 00 01 00 74 05 44 0f b6 65 51 48 8b 45 00 a9 00 00 01 00 75 0a 48 8b 45 08 a8 01 75 02 <0f> 0b 48 8b 45 00 44>
RSP: 0018:ffffba5a8aaffe30 EFLAGS: 00010246
RAX: ffffe4160c36f748 RBX: ffff9b8200000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000005 RDI: ffff9b8200000000
RBP: ffffe4160c000000 R08: ffff9b828a4f882c R09: ffff9b838a4f880b
R10: ffffffffffffffff R11: 0000000050424752 R12: 0000000000000000
R13: ffff9b81fe46d120 R14: 0000000000000000 R15: 0000000000000040
FS:  00007f5fe1b93640(0000) GS:ffff9b830eb40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f60082cf000 CR3: 000000038f208000 CR4: 00000000003506e0

If it happens again I'll try to note down the exact command used. I'm just trying to get an mjpeg stream into the output device with gst-launch, and it's proving harder than expected.

I'm trying to use an akvcam device as a tool to stream over e.g. Google Meet by composing my scene with OBS. While I'm able to actually stream some video through the virtual camera, the output looks weird with the scene being replicated multiple times and in grayscale.

Here's what I mean:

I guess something is off either in my akvcam configuration, in my OBS recording configuration, in my ffmpeg command or in any valid permutation of the interactions between the three tools :-)
Thing is, I have no clue what might be the source of the issue.

Here's my akvcam configuration file:

[Cameras]
cameras/size = 2

cameras/1/type = output
cameras/1/mode = mmap, userptr, rw
cameras/1/description = Virtual Camera (output device)
cameras/1/formats = 2

cameras/2/type = capture
cameras/2/mode = mmap, rw
cameras/2/description = Virtual Camera
cameras/2/formats = 1, 2

[Formats]
formats/size = 2

# -> into akvcam
formats/1/format = YUY2
formats/1/width = 3840
formats/1/height = 2160
formats/1/fps = 30/1

# <- out of akvcam
formats/2/format = RGB24
formats/2/width = 3840
formats/2/height = 2160
formats/2/fps = 20/1, 15/2

[Connections]
connections/size = 1
connections/1/connection = 1:2

As well as my OBS recording configuration:

And the ffmpeg command that I use to connect OBS to akvcam:

ffmpeg -i udp://localhost:12345 -f v4l2 -s 3840x2160 /dev/video4

Not having luck, perhaps more information in Wiki that can answer the following collection of random thoughts:

Does akvcam scale/resize?

I just want to send 720p or 1080p video to akvcam and whatever resolution is taken from "capture" wants to pull, it gets (downscalled), but I've been fighting all day on different INIs.

It's not clear if the order is important (output must before capture in that order), I tried changing the order and perhaps missed something but it didn't work.

in:
[Connections]
connections/size = 1
connections/1/connection = 1:2

(connections/n/connection = ...) is n important ? is n effect the /dev/videoX (X ~= n )?

quoted https://github.com/webcamoid/akvcam/wiki/Configure-the-cameras
'simple straight forward INI like configuration'

[fwiw: at * commit 5f94c37 (HEAD -> master, tag: 1.0.4, origin/master, origin/HEAD)]

At first I thought it was an issue with more than one connection, but a single has same issues:

It has been difficult to document what I have so far, because after akvcam stops responding to "capture" programs (in this case cheese for reference), the system is unstable in various ways. Reboots usually lock up, removing the driver fails (it's "busy") so can't reload. Often before a reboot, the system usually stops responding in some fashion (keyboard, mouse, screen lockups].

I've tried older kernels (4.15, 4.18, currently on latest hwe 5.3 / all lowlatency).
At this point not sure what to do -- will continue to poke at it and try to make it usable.

config.ini:

[Cameras]
cameras/size = 2

# /dev/videoN
cameras/1/type = output
cameras/1/mode = mmap, userptr, rw
cameras/1/description = VCam1(4:3/720p)
cameras/1/formats = 1

# /dev/videoN+1
cameras/2/type = capture
cameras/2/mode = mmap, userptr, rw
cameras/2/description = VCam1(4:3/480p/720p)
cameras/2/formats = 2, 3

[Formats]
formats/size = 3

# formats for "output" (into akvcam)
formats/1/format = RGB24, YUY2
formats/1/width = 960
formats/1/height = 720
formats/1/fps = 30/1, 15/1, 15/2

# formats for "capture" (output from akvcam)
formats/2/format = RGB24
formats/2/width = 640
formats/2/height = 480
formats/2/fps = 30/1, 15/1, 15/2

formats/3/format = RGB24
formats/3/width = 960
formats/3/height = 720
formats/3/fps = 30/1, 15/1, 15/2

[Connections]
connections/size = 1
connections/1/connection = 1:2

then simple run cheese at it twice.. Second time Cheese complains about the device not working:

dx@wdp76:~$ sudo modprobe akvcam
dx@wdp76:~$ cheese

(cheese:4499): Gtk-WARNING **: 16:59:30.464: Theme parsing error: cheese.css:7:35: The style property GtkScrollbar:min-slider-length is deprecated and shouldn't be used anymore. It will be removed in a future version
Gtk-Message: 16:59:33.749: GtkDialog mapped without a transient parent. This is discouraged.
dx@wdp76:~$ cheese

(cheese:4584): Gtk-WARNING **: 16:59:41.872: Theme parsing error: cheese.css:7:35: The style property GtkScrollbar:min-slider-length is deprecated and shouldn't be used anymore. It will be removed in a future version
Gtk-Message: 16:59:45.052: GtkDialog mapped without a transient parent. This is discouraged.

(cheese:4584): cheese-WARNING **: 16:59:46.415: Device '/dev/video3' is busy: gstv4l2object.c(3754): gst_v4l2_object_set_format_full (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin19/GstV4l2Src:v4l2src2:
Call to S_FMT failed for RGB3 @ 640x480: Device or resource busy

dx@wdp76:~$ sudo rmmod akvcam
dx@wdp76:~$ dmesg

[...]

[ 229.307847] BUG: unable to handle page fault for address: ffffffffc0e2de9a
[ 229.307849] #PF: supervisor instruction fetch in kernel mode
[ 229.307850] #PF: error_code(0x0010) - not-present page
[ 229.307850] PGD 34bc0e067 P4D 34bc0e067 PUD 34bc10067 PMD 7e792f067 PTE 0
[ 229.307852] Oops: 0010 [#1] PREEMPT SMP PTI
[ 229.307854] CPU: 3 PID: 4565 Comm: akvcam-thread-3 Tainted: P C OE 5.3.0-51-lowlatency #44~18.04.2-Ubuntu
[ 229.307854] Hardware name: System76 Wild Dog Pro/Z370 HD3P-CF, BIOS F5 Z5 12/15/2017
[ 229.307856] RIP: 0010:0xffffffffc0e2de9a
[ 229.307858] Code: Bad RIP value.
[ 229.307858] RSP: 0018:ffffb0b8c38b7ef0 EFLAGS: 00010246
[ 229.307859] RAX: 0000000000000000 RBX: ffff9b4405ba3700 RCX: 0000000000000000
[ 229.307860] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000000
[ 229.307860] RBP: ffffb0b8c38b7f00 R08: 0000000000000000 R09: 000000000002a000
[ 229.307874] R10: ffffb0b8c00e7e18 R11: 0000000000000361 R12: 0000000000000021
[ 229.307875] R13: ffffb0b8c384fce8 R14: ffff9b4405ba3700 R15: ffff9b43ec0fcd80
[ 229.307876] FS: 0000000000000000(0000) GS:ffff9b448e8c0000(0000) knlGS:0000000000000000
[ 229.307876] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 229.307877] CR2: ffffffffc0e2de70 CR3: 000000034bc0a006 CR4: 00000000003606e0
[ 229.307878] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 229.307878] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 229.307879] Call Trace:
[ 229.307882] kthread+0x121/0x140
[ 229.307883] ? kthread_park+0xb0/0xb0
[ 229.307897] ret_from_fork+0x35/0x40
[ 229.307899] Modules linked in: xt_CHECKSUM iptable_mangle xt_MASQUERADE iptable_nat nf_nat xt_conntrack nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c ipt_REJECT nf_reject_ipv4 xt_tcpudp bridge stp llc ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter bpfilter typec_displayport aufs overlay binfmt_misc nls_iso8859_1 nvidia_uvm(OE) nvidia_drm(POE) nvidia_modeset(POE) nvidia(POE) intel_rapl_msr mei_hdcp intel_rapl_common x86_pkg_temp_thermal intel_powerclamp snd_hda_codec_hdmi coretemp kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_codec_realtek snd_hda_codec_generic ledtrig_audio uvcvideo aesni_intel snd_hda_intel snd_intel_nhlt v4l2_common videobuf2_vmalloc aes_x86_64 drm_kms_helper snd_hda_codec crypto_simd cryptd videobuf2_memops snd_usb_audio snd_hda_core glue_helper snd_usbmidi_lib snd_hwdep intel_cstate videobuf2_v4l2 snd_seq_midi intel_rapl_perf videobuf2_common snd_seq_midi_event drm snd_rawmidi snd_seq videodev ipmi_devintf
[ 229.307914] ipmi_msghandler joydev wmi_bmof mc input_leds snd_pcm fb_sys_fops ucsi_ccg snd_seq_device syscopyarea typec_ucsi snd_timer sysfillrect typec sysimgblt snd mei_me soundcore mei ie31200_edac acpi_pad mac_hid sch_fq_codel cuse parport_pc ppdev lp parport binder_linux ashmem_linux(CE) ip_tables x_tables autofs4 hid_logitech_hidpp hid_logitech_dj hid_plantronics hid_generic usbhid hid e1000e ahci libahci i2c_nvidia_gpu wmi video [last unloaded: akvcam]
[ 229.307924] CR2: ffffffffc0e2de9a
[ 229.307925] ---[ end trace cbf1559a98be27fc ]---
[ 229.307926] RIP: 0010:0xffffffffc0e2de9a
[ 229.307927] Code: Bad RIP value.
[ 229.307927] RSP: 0018:ffffb0b8c38b7ef0 EFLAGS: 00010246
[ 229.307928] RAX: 0000000000000000 RBX: ffff9b4405ba3700 RCX: 0000000000000000
[ 229.307928] RDX: 0000000000000000 RSI: 0000000000000246 RDI: 0000000000000000
[ 229.307929] RBP: ffffb0b8c38b7f00 R08: 0000000000000000 R09: 000000000002a000
[ 229.307929] R10: ffffb0b8c00e7e18 R11: 0000000000000361 R12: 0000000000000021
[ 229.307930] R13: ffffb0b8c384fce8 R14: ffff9b4405ba3700 R15: ffff9b43ec0fcd80
[ 229.307931] FS: 0000000000000000(0000) GS:ffff9b448e8c0000(0000) knlGS:0000000000000000
[ 229.307931] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 229.307932] CR2: ffffffffc0e2de70 CR3: 000000034bc0a006 CR4: 00000000003606e0
[ 229.307932] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 229.307933] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Hello

Is there a way to use an akvcam webcam with a qemu virtual machine ?

I assume this needs the akvcam to emulate an usb webcam with a vendoreid and a productid or something else.

Thanks

compilation error with kernel 5.10-rc6
(same error since kernel 5.10-rc1)
make.log

Hello,
I am interested in writing a video stream from OpenCV to akvcam.
Is it possible? Would you share a simple code snippet?

When I try to load the driver, it gives me an error. Here is the full input and output:

$ sudo modprobe videodev
$ sudo insmod akvcam.ko
insmod: ERROR: could not insert module akvcam.ko: Operation not permitted

Thanks for reading, any help would be apreciated

I've had a couple problems with make files lately, so maybe I'm the problem lol

getting this result for sudo make dkms_install

dkms remove akvcam/1.2.0 --all
make: dkms: Command not found
make: [Makefile:63: dkms_uninstall] Error 127 (ignored)
rm -rvf /usr/src/akvcam-1.2.0
rm -rvf /usr/src/akvcam-1.2.0
mkdir -p /usr/src/akvcam-1.2.0
cp -f Makefile /usr/src/akvcam-1.2.0
cp -f dkms.conf /usr/src/akvcam-1.2.0
cp -f *.h /usr/src/akvcam-1.2.0
cp -f *.c /usr/src/akvcam-1.2.0
dkms install akvcam/1.2.0
make: dkms: Command not found
make: *** [Makefile:57: dkms_install] Error 127

Wiki mentions that other formats will be implemented. Is that planed for the near future? I would like to use YUY2 for my output device because the capture device is using YUY2 an so I could skip transcoding.

The wiki says to replace version with the version, but I don't know where to find it.
sudo mkdir -p /usr/src/akvcam-${VERSION}

When I use sudo make on Ubuntu Linux running on AWS it's all fine until it needs to build the modules. Can anyone please help me fix this error.

make -C /lib/modules/5.4.0-1029-aws/build M=/home/ubuntu/akvcam/src  modules
make[1]: Entering directory '/usr/src/linux-headers-5.4.0-1029-aws'
  CC [M]  /home/ubuntu/akvcam/src/module.o
  CC [M]  /home/ubuntu/akvcam/src/attributes.o
  CC [M]  /home/ubuntu/akvcam/src/buffer.o
  CC [M]  /home/ubuntu/akvcam/src/buffers.o
  CC [M]  /home/ubuntu/akvcam/src/controls.o
  CC [M]  /home/ubuntu/akvcam/src/device.o
  CC [M]  /home/ubuntu/akvcam/src/driver.o
  CC [M]  /home/ubuntu/akvcam/src/events.o
  CC [M]  /home/ubuntu/akvcam/src/file_read.o
  CC [M]  /home/ubuntu/akvcam/src/format.o
  CC [M]  /home/ubuntu/akvcam/src/frame.o
  CC [M]  /home/ubuntu/akvcam/src/global_deleter.o

  CC [M]  /home/ubuntu/akvcam/src/ioctl.o
  CC [M]  /home/ubuntu/akvcam/src/list.o
  CC [M]  /home/ubuntu/akvcam/src/log.o
  CC [M]  /home/ubuntu/akvcam/src/map.o
  CC [M]  /home/ubuntu/akvcam/src/mmap.o
  CC [M]  /home/ubuntu/akvcam/src/node.o
  CC [M]  /home/ubuntu/akvcam/src/rbuffer.o
  CC [M]  /home/ubuntu/akvcam/src/settings.o
  CC [M]  /home/ubuntu/akvcam/src/utils.o
  LD [M]  /home/ubuntu/akvcam/src/akvcam.o
  Building modules, stage 2.
  MODPOST 1 modules
ERROR: "video_device_release_empty" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "video_device_release" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "v4l2_device_unregister" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "__video_register_device" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "v4l2_device_register" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "video_device_alloc" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
ERROR: "video_unregister_device" [/home/ubuntu/akvcam/src/akvcam.ko] undefined!
scripts/Makefile.modpost:93: recipe for target '__modpost' failed
make[2]: *** [__modpost] Error 1
Makefile:1670: recipe for target 'modules' failed
make[1]: *** [modules] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.4.0-1029-aws'
Makefile:48: recipe for target 'all' failed
make: *** [all] Error 2

On a Pi 4, most recent everything (apt update & apt dist-upgrade, etc etc, build environment is good (OpenCV compiles from scratch, etc). V4l2loopback is most recent version (apt package uninstalled and distro compiled and installed).
During make, I get:

make -C /lib/modules/5.10.11-v7l+/build M=/home/pi/akvcam/src modules
make[1]: Entering directory '/usr/src/linux-headers-5.10.11-v7l+'
CC [M] /home/pi/akvcam/src/module.o
CC [M] /home/pi/akvcam/src/attributes.o
CC [M] /home/pi/akvcam/src/buffers.o
CC [M] /home/pi/akvcam/src/controls.o
CC [M] /home/pi/akvcam/src/device.o
CC [M] /home/pi/akvcam/src/driver.o
CC [M] /home/pi/akvcam/src/file_read.o
CC [M] /home/pi/akvcam/src/format.o
CC [M] /home/pi/akvcam/src/frame.o
CC [M] /home/pi/akvcam/src/global_deleter.o
CC [M] /home/pi/akvcam/src/ioctl.o
CC [M] /home/pi/akvcam/src/list.o
CC [M] /home/pi/akvcam/src/log.o
CC [M] /home/pi/akvcam/src/map.o
CC [M] /home/pi/akvcam/src/rbuffer.o
CC [M] /home/pi/akvcam/src/settings.o
CC [M] /home/pi/akvcam/src/utils.o
LD [M] /home/pi/akvcam/src/akvcam.o
MODPOST /home/pi/akvcam/src/Module.symvers
ERROR: modpost: "__aeabi_ldivmod" [/home/pi/akvcam/src/akvcam.ko] undefined!
make[2]: *** [scripts/Makefile.modpost:111: /home/pi/akvcam/src/Module.symvers] Error 1
make[2]: *** Deleting file '/home/pi/akvcam/src/Module.symvers'
make[1]: *** [Makefile:1712: modules] Error 2
make[1]: Leaving directory '/usr/src/linux-headers-5.10.11-v7l+'
make: *** [Makefile:44: all] Error 2

Not really unlike #40. I did the

sudo depmod -a
sudo modprobe v4l2-common <-- this module wasn't found
sudo modprobe videobuf2-core <-- neither was this one
sudo modprobe videobuf2-v4l2
sudo modprobe videobuf2-vmalloc
sudo modprobe videodev

bit, and the modules noted weren't found. I'm not sure what to try next...?
Thank you for your time and consideration.

In v4l2loopback, there is a driver parameter called video_nr, which specifies the device-node minor number. Is it possible to specify this in akvcam? I basically want to stop akvcam to occupy /dev/video0 and /dev/video1.

Hello,

I want to reproduce the functionality of FakeWebcam as
import numpy as np
import cv2
import pyfakewebcam

file = 'obama.mp4'

cap = cv2.VideoCapture(file)
width = int(cap.get(cv2.CAP_PROP_FRAME_WIDTH))
height = int(cap.get(cv2.CAP_PROP_FRAME_HEIGHT))

#LINE 1
camera = pyfakewebcam.FakeWebcam('/dev/video1', width, height)

while(True):
ret, frame = cap.read()
frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
#Line 2
camera.schedule_frame(frame)

When everything done, release the capture

cap.release()
cv2.destroyAllWindows()

As in the Line#1, I wish to create a virtual Camera.
Like Line 2, I want to dump some images to the device
and I want to see them using Virtual Camera in different window.

Could anyone explain how to di Line#1 and Line webcamoid/webcamoid#243

This is on a Ubuntu 18.04.4 LTS setup running on intel i3-3240 w/ 4GB DDR3 RAM, using Liquorix kernel: 5.8.0-10.1-liquorix-amd64 #1 ZEN SMP PREEMPT liquorix 5.8-8ubuntu1~bionic (2020-09-17) x86_64 x86_64 x86_64 GNU/Linux

Error during installation process (com.akvcamprj.akvcam):
Execution failed (Unexpected exit code: 255): "dkms install akvcam/1.1.1"

I got akvcam working, and I tested video ouput and video capture. ffmpeg/ffplay example from the wiki is working nicely and I can see the virtual capture device with softwares like Cheese.
BUT
While not writing to ouput device nor reading from capture device, I got kernel crash (Ubuntu 20.04.1, Linux 5.4.0-53-generic).
This happens at random times, but very quickly.
Here is a sample trace :

Nov 20 01:11:26 MyComputer kernel: [   92.981085] ------------[ cut here ]------------
Nov 20 01:11:26 MyComputer kernel: [   92.981088] kernel BUG at mm/slub.c:3995!
Nov 20 01:11:26 MyComputer kernel: [   92.981098] invalid opcode: 0000 [#1] SMP PTI
Nov 20 01:11:26 MyComputer kernel: [   92.981102] CPU: 1 PID: 5826 Comm: Socket Thread Tainted: P           O      5.4.0-53-generic #59-Ubuntu
Nov 20 01:11:26 MyComputer kernel: [   92.981104] Hardware name: Dell Inc. XPS 15 7590/0VYV0G, BIOS 1.8.1 07/03/2020
Nov 20 01:11:26 MyComputer kernel: [   92.981110] RIP: 0010:kfree+0x1de/0x250
Nov 20 01:11:26 MyComputer kernel: [   92.981114] Code: ff ff 49 8b 04 24 45 31 ed a9 00 00 01 00 74 06 45 0f b6 6c 24 51 49 8b 04 24 a9 00 00 01 00 75 0b 49 8b 44 24 08 a8 01 75 02 <0f> 0b 49 8b 04 24 44 89 e9 ba ff ff ff ff be 06 00 00 00 d3 e2 48
Nov 20 01:11:26 MyComputer kernel: [   92.981116] RSP: 0018:ffffaa270167faa0 EFLAGS: 00010246
Nov 20 01:11:26 MyComputer kernel: [   92.981119] RAX: ffffe0f6912021c8 RBX: ffff93320808818f RCX: 0000000000000000
Nov 20 01:11:26 MyComputer kernel: [   92.981121] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff93320808818f
Nov 20 01:11:26 MyComputer kernel: [   92.981123] RBP: ffffaa270167fac0 R08: 0000000000000010 R09: ffff9332407d5d00
Nov 20 01:11:26 MyComputer kernel: [   92.981125] R10: 0000000000000000 R11: ffff9332407d5000 R12: ffffe0f691202200
Nov 20 01:11:26 MyComputer kernel: [   92.981127] R13: 0000000000000000 R14: 0000000000000000 R15: ffff93320808825b
Nov 20 01:11:26 MyComputer kernel: [   92.981129] FS:  00007f6ce86be700(0000) GS:ffff933230040000(0000) knlGS:0000000000000000
Nov 20 01:11:26 MyComputer kernel: [   92.981132] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Nov 20 01:11:26 MyComputer kernel: [   92.981134] CR2: 000055ec36ef6e38 CR3: 0000000417412004 CR4: 00000000003606e0
Nov 20 01:11:26 MyComputer kernel: [   92.981136] Call Trace:
Nov 20 01:11:26 MyComputer kernel: [   92.981143]  do_sys_poll+0x125/0x520
Nov 20 01:11:26 MyComputer kernel: [   92.981149]  ? __enqueue_entity+0x96/0xa0
Nov 20 01:11:26 MyComputer kernel: [   92.981154]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981158]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981160]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981163]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981166]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981169]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981172]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981175]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981178]  ? poll_select_finish+0x210/0x210
Nov 20 01:11:26 MyComputer kernel: [   92.981181]  __x64_sys_poll+0x3b/0x140
Nov 20 01:11:26 MyComputer kernel: [   92.981187]  do_syscall_64+0x57/0x190
Nov 20 01:11:26 MyComputer kernel: [   92.981192]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
Nov 20 01:11:26 MyComputer kernel: [   92.981195] RIP: 0033:0x7f6cf8f4aaff
Nov 20 01:11:26 MyComputer kernel: [   92.981198] Code: 54 24 1c 48 89 74 24 10 48 89 7c 24 08 e8 79 1c f8 ff 8b 54 24 1c 48 8b 74 24 10 41 89 c0 48 8b 7c 24 08 b8 07 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 2b 44 89 c7 89 44 24 08 e8 ad 1c f8 ff 8b 44
Nov 20 01:11:26 MyComputer kernel: [   92.981200] RSP: 002b:00007f6ce86bd6f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000007
Nov 20 01:11:26 MyComputer kernel: [   92.981203] RAX: ffffffffffffffda RBX: 00007f6cb81c3000 RCX: 00007f6cf8f4aaff
Nov 20 01:11:26 MyComputer kernel: [   92.981205] RDX: 00000000ffffffff RSI: 0000000000000036 RDI: 00007f6ce86bd780
Nov 20 01:11:26 MyComputer kernel: [   92.981206] RBP: 0000000000000001 R08: 0000000000000000 R09: 00007f6cf8c65fd0
Nov 20 01:11:26 MyComputer kernel: [   92.981209] R10: 00007f6ce86bd9f8 R11: 0000000000000293 R12: 0000000000000036
Nov 20 01:11:26 MyComputer kernel: [   92.981210] R13: 00007f6ce86bd780 R14: ffffffffffffffca R15: 00000000ffffffff
Nov 20 01:11:26 MyComputer kernel: [   92.981214] Modules linked in: rfcomm xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user xfrm_algo xt_addrtype iptable_filter iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c bpfilter br_netfilter bridge stp llc vboxnetadp(O) vboxnetflt(O) vboxdrv(O) ccm aufs cmac algif_hash algif_skcipher overlay af_alg bnep dm_crypt snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic nvidia_uvm(O) x86_pkg_temp_thermal intel_powerclamp coretemp mei_hdcp joydev nvidia_drm(PO) kvm_intel snd_sof_pci intel_rapl_msr nvidia_modeset(PO) snd_sof_intel_hda_common kvm snd_soc_hdac_hda snd_sof_intel_hda snd_sof_intel_byt snd_sof_intel_ipc crct10dif_pclmul nls_iso8859_1 snd_sof snd_sof_xtensa_dsp snd_hda_ext_core ghash_clmulni_intel snd_soc_acpi_intel_match snd_soc_acpi aesni_intel snd_soc_core crypto_simd cryptd glue_helper snd_compress ac97_bus snd_pcm_dmaengine dell_laptop nvidia(PO) ledtrig_audio rapl snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core
Nov 20 01:11:26 MyComputer kernel: [   92.981256]  snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event intel_cstate snd_rawmidi dell_wmi btusb btrtl input_leds btbcm btintel dell_smbios bluetooth uvcvideo iwlmvm videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 serio_raw dcdbas mac80211 ecdh_generic cdc_acm videobuf2_common ecc snd_seq libarc4 dell_wmi_descriptor i915 wmi_bmof intel_wmi_thunderbolt snd_seq_device snd_timer snd iwlwifi mxm_wmi drm_kms_helper cfg80211 i2c_algo_bit processor_thermal_device rtsx_pci_ms ucsi_acpi fb_sys_fops intel_rapl_common typec_ucsi mei_me soundcore memstick hid_multitouch syscopyarea typec sysfillrect mei sysimgblt intel_soc_dts_iosf intel_pch_thermal mac_hid int3403_thermal int340x_thermal_zone intel_hid dell_smo8800 sparse_keymap acpi_pad int3400_thermal acpi_thermal_rel sch_fq_codel parport_pc ppdev lp parport akvcam(O) videodev mc drm ip_tables x_tables autofs4 hid_generic rtsx_pci_sdmmc crc32_pclmul nvme psmouse i2c_i801 nvme_core rtsx_pci intel_lpss_pci thunderbolt intel_lpss ahci idma64
Nov 20 01:11:26 MyComputer kernel: [   92.981303]  libahci virt_dma i2c_hid hid video pinctrl_cannonlake wmi pinctrl_intel
Nov 20 01:11:26 MyComputer kernel: [   92.981312] ---[ end trace 2837fe6b6634f791 ]---
Nov 20 01:11:26 MyComputer kernel: [   92.981315] RIP: 0010:kfree+0x1de/0x250
Nov 20 01:11:26 MyComputer kernel: [   92.981318] Code: ff ff 49 8b 04 24 45 31 ed a9 00 00 01 00 74 06 45 0f b6 6c 24 51 49 8b 04 24 a9 00 00 01 00 75 0b 49 8b 44 24 08 a8 01 75 02 <0f> 0b 49 8b 04 24 44 89 e9 ba ff ff ff ff be 06 00 00 00 d3 e2 48
Nov 20 01:11:26 MyComputer kernel: [   92.981320] RSP: 0018:ffffaa270167faa0 EFLAGS: 00010246
Nov 20 01:11:26 MyComputer kernel: [   92.981322] RAX: ffffe0f6912021c8 RBX: ffff93320808818f RCX: 0000000000000000
Nov 20 01:11:26 MyComputer kernel: [   92.981324] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff93320808818f
Nov 20 01:11:26 MyComputer kernel: [   92.981326] RBP: ffffaa270167fac0 R08: 0000000000000010 R09: ffff9332407d5d00
Nov 20 01:11:26 MyComputer kernel: [   92.981327] R10: 0000000000000000 R11: ffff9332407d5000 R12: ffffe0f691202200
Nov 20 01:11:26 MyComputer kernel: [   92.981329] R13: 0000000000000000 R14: 0000000000000000 R15: ffff93320808825b
Nov 20 01:11:26 MyComputer kernel: [   92.981332] FS:  00007f6ce86be700(0000) GS:ffff933230040000(0000) knlGS:0000000000000000
Nov 20 01:11:26 MyComputer kernel: [   92.981334] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Nov 20 01:11:26 MyComputer kernel: [   92.981335] CR2: 000055ec36ef6e38 CR3: 0000000417412004 CR4: 00000000003606e0
Nov 20 01:11:29 MyComputer kernel: [   96.582260] general protection fault: 0000 [#2] SMP PTI
Nov 20 01:11:29 MyComputer kernel: [   96.582271] CPU: 10 PID: 5462 Comm: cheese Tainted: P      D    O      5.4.0-53-generic #59-Ubuntu
Nov 20 01:11:29 MyComputer kernel: [   96.582275] Hardware name: Dell Inc. XPS 15 7590/0VYV0G, BIOS 1.8.1 07/03/2020
Nov 20 01:11:29 MyComputer kernel: [   96.582284] RIP: 0010:__kmalloc+0x9e/0x280
Nov 20 01:11:29 MyComputer kernel: [   96.582289] Code: 87 01 00 00 4d 8b 01 65 49 8b 50 08 65 4c 03 05 40 87 d6 7d 4d 8b 20 4d 85 e4 0f 84 9c 01 00 00 41 8b 41 20 49 8b 39 4c 01 e0 <48> 8b 18 48 89 c1 49 33 99 70 01 00 00 4c 89 e0 48 0f c9 48 31 cb
Nov 20 01:11:29 MyComputer kernel: [   96.582293] RSP: 0018:ffffaa2704af7790 EFLAGS: 00010202
Nov 20 01:11:29 MyComputer kernel: [   96.582298] RAX: 7ddc90cf08088a8f RBX: 0000000000000000 RCX: 0000000000000000
Nov 20 01:11:29 MyComputer kernel: [   96.582302] RDX: 00000000000003c5 RSI: 0000000000002cc0 RDI: 000000000002f120
Nov 20 01:11:29 MyComputer kernel: [   96.582305] RBP: ffffaa2704af77c0 R08: ffff9332302af120 R09: ffff93322e406f40
Nov 20 01:11:29 MyComputer kernel: [   96.582308] R10: 0000000000000001 R11: 0000000000000008 R12: 7ddc90cf08088a8f
Nov 20 01:11:29 MyComputer kernel: [   96.582311] R13: 0000000000002cc0 R14: 0000000000000100 R15: ffff93322e406f40
Nov 20 01:11:29 MyComputer kernel: [   96.582316] FS:  00007fc021a83a80(0000) GS:ffff933230280000(0000) knlGS:0000000000000000
Nov 20 01:11:29 MyComputer kernel: [   96.582319] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Nov 20 01:11:29 MyComputer kernel: [   96.582322] CR2: 00007fc00b15b020 CR3: 000000039980c001 CR4: 00000000003606e0
Nov 20 01:11:29 MyComputer kernel: [   96.582325] Call Trace:
Nov 20 01:11:29 MyComputer kernel: [   96.582335]  ? sg_kmalloc+0x1a/0x30
Nov 20 01:11:29 MyComputer kernel: [   96.582342]  sg_kmalloc+0x1a/0x30
Nov 20 01:11:29 MyComputer kernel: [   96.582348]  __sg_alloc_table+0x10b/0x170
Nov 20 01:11:29 MyComputer kernel: [   96.582354]  sg_alloc_table+0x24/0x60
Nov 20 01:11:29 MyComputer kernel: [   96.582360]  ? sg_init_one+0x80/0x80
Nov 20 01:11:29 MyComputer kernel: [   96.582441]  i915_sg_trim+0x40/0x100 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.582530]  shmem_get_pages+0x2e6/0x650 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.582539]  ? blocking_notifier_call_chain+0x5b/0x70
Nov 20 01:11:29 MyComputer kernel: [   96.582546]  ? _cond_resched+0x19/0x30
Nov 20 01:11:29 MyComputer kernel: [   96.582551]  ? mutex_lock_interruptible+0x13/0x40
Nov 20 01:11:29 MyComputer kernel: [   96.582640]  ? i915_gem_object_pin_map+0xbb/0x1a0 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.582719]  ____i915_gem_object_get_pages+0x22/0x40 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.582799]  __i915_gem_object_get_pages+0x5b/0x70 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.582887]  __i915_vma_do_pin+0x3ee/0x470 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.582970]  eb_lookup_vmas+0x688/0xb70 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.583050]  ? eb_pin_engine+0x255/0x410 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.583128]  i915_gem_do_execbuffer+0x38f/0xc20 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.583139]  ? mem_cgroup_commit_charge+0x63/0x490
Nov 20 01:11:29 MyComputer kernel: [   96.583147]  ? shmem_getpage_gfp+0x338/0x940
Nov 20 01:11:29 MyComputer kernel: [   96.583152]  ? __kmalloc_node+0x20e/0x330
Nov 20 01:11:29 MyComputer kernel: [   96.583224]  i915_gem_execbuffer2_ioctl+0x2c3/0x3d0 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.583298]  ? i915_gem_execbuffer_ioctl+0x2d0/0x2d0 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.583336]  drm_ioctl_kernel+0xae/0xf0 [drm]
Nov 20 01:11:29 MyComputer kernel: [   96.583365]  drm_ioctl+0x234/0x3d0 [drm]
Nov 20 01:11:29 MyComputer kernel: [   96.583436]  ? i915_gem_execbuffer_ioctl+0x2d0/0x2d0 [i915]
Nov 20 01:11:29 MyComputer kernel: [   96.583445]  do_vfs_ioctl+0x407/0x670
Nov 20 01:11:29 MyComputer kernel: [   96.583453]  ? do_user_addr_fault+0x216/0x450
Nov 20 01:11:29 MyComputer kernel: [   96.583458]  ksys_ioctl+0x67/0x90
Nov 20 01:11:29 MyComputer kernel: [   96.583464]  __x64_sys_ioctl+0x1a/0x20
Nov 20 01:11:29 MyComputer kernel: [   96.583471]  do_syscall_64+0x57/0x190
Nov 20 01:11:29 MyComputer kernel: [   96.583478]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
Nov 20 01:11:29 MyComputer kernel: [   96.583483] RIP: 0033:0x7fc0233ce50b
Nov 20 01:11:29 MyComputer kernel: [   96.583488] Code: 0f 1e fa 48 8b 05 85 39 0d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 55 39 0d 00 f7 d8 64 89 01 48
Nov 20 01:11:29 MyComputer kernel: [   96.583491] RSP: 002b:00007ffc03500448 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
Nov 20 01:11:29 MyComputer kernel: [   96.583497] RAX: ffffffffffffffda RBX: 00005565ceb558f0 RCX: 00007fc0233ce50b
Nov 20 01:11:29 MyComputer kernel: [   96.583500] RDX: 00007ffc03500460 RSI: 0000000040406469 RDI: 000000000000000e
Nov 20 01:11:29 MyComputer kernel: [   96.583502] RBP: 00007ffc035004f0 R08: 0000000000000001 R09: 0000000000000000
Nov 20 01:11:29 MyComputer kernel: [   96.583505] R10: 00007ffc03500510 R11: 0000000000000246 R12: 00007fc01b2dfb28
Nov 20 01:11:29 MyComputer kernel: [   96.583508] R13: 0000000000000000 R14: 00007ffc03500460 R15: 000000000000000e
Nov 20 01:11:29 MyComputer kernel: [   96.583513] Modules linked in: rfcomm xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xfrm_user xfrm_algo xt_addrtype iptable_filter iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c bpfilter br_netfilter bridge stp llc vboxnetadp(O) vboxnetflt(O) vboxdrv(O) ccm aufs cmac algif_hash algif_skcipher overlay af_alg bnep dm_crypt snd_hda_codec_hdmi snd_hda_codec_realtek snd_hda_codec_generic nvidia_uvm(O) x86_pkg_temp_thermal intel_powerclamp coretemp mei_hdcp joydev nvidia_drm(PO) kvm_intel snd_sof_pci intel_rapl_msr nvidia_modeset(PO) snd_sof_intel_hda_common kvm snd_soc_hdac_hda snd_sof_intel_hda snd_sof_intel_byt snd_sof_intel_ipc crct10dif_pclmul nls_iso8859_1 snd_sof snd_sof_xtensa_dsp snd_hda_ext_core ghash_clmulni_intel snd_soc_acpi_intel_match snd_soc_acpi aesni_intel snd_soc_core crypto_simd cryptd glue_helper snd_compress ac97_bus snd_pcm_dmaengine dell_laptop nvidia(PO) ledtrig_audio rapl snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hda_core
Nov 20 01:11:29 MyComputer kernel: [   96.583575]  snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event intel_cstate snd_rawmidi dell_wmi btusb btrtl input_leds btbcm btintel dell_smbios bluetooth uvcvideo iwlmvm videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 serio_raw dcdbas mac80211 ecdh_generic cdc_acm videobuf2_common ecc snd_seq libarc4 dell_wmi_descriptor i915 wmi_bmof intel_wmi_thunderbolt snd_seq_device snd_timer snd iwlwifi mxm_wmi drm_kms_helper cfg80211 i2c_algo_bit processor_thermal_device rtsx_pci_ms ucsi_acpi fb_sys_fops intel_rapl_common typec_ucsi mei_me soundcore memstick hid_multitouch syscopyarea typec sysfillrect mei sysimgblt intel_soc_dts_iosf intel_pch_thermal mac_hid int3403_thermal int340x_thermal_zone intel_hid dell_smo8800 sparse_keymap acpi_pad int3400_thermal acpi_thermal_rel sch_fq_codel parport_pc ppdev lp parport akvcam(O) videodev mc drm ip_tables x_tables autofs4 hid_generic rtsx_pci_sdmmc crc32_pclmul nvme psmouse i2c_i801 nvme_core rtsx_pci intel_lpss_pci thunderbolt intel_lpss ahci idma64
Nov 20 01:11:29 MyComputer kernel: [   96.583641]  libahci virt_dma i2c_hid hid video pinctrl_cannonlake wmi pinctrl_intel
Nov 20 01:11:29 MyComputer kernel: [   96.583656] ---[ end trace 2837fe6b6634f792 ]---
Nov 20 01:11:29 MyComputer kernel: [   96.583662] RIP: 0010:kfree+0x1de/0x250
Nov 20 01:11:29 MyComputer kernel: [   96.583667] Code: ff ff 49 8b 04 24 45 31 ed a9 00 00 01 00 74 06 45 0f b6 6c 24 51 49 8b 04 24 a9 00 00 01 00 75 0b 49 8b 44 24 08 a8 01 75 02 <0f> 0b 49 8b 04 24 44 89 e9 ba ff ff ff ff be 06 00 00 00 d3 e2 48
Nov 20 01:11:29 MyComputer kernel: [   96.583670] RSP: 0018:ffffaa270167faa0 EFLAGS: 00010246
Nov 20 01:11:29 MyComputer kernel: [   96.583674] RAX: ffffe0f6912021c8 RBX: ffff93320808818f RCX: 0000000000000000
Nov 20 01:11:29 MyComputer kernel: [   96.583677] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff93320808818f
Nov 20 01:11:29 MyComputer kernel: [   96.583680] RBP: ffffaa270167fac0 R08: 0000000000000010 R09: ffff9332407d5d00
Nov 20 01:11:29 MyComputer kernel: [   96.583683] R10: 0000000000000000 R11: ffff9332407d5000 R12: ffffe0f691202200
Nov 20 01:11:29 MyComputer kernel: [   96.583685] R13: 0000000000000000 R14: 0000000000000000 R15: ffff93320808825b
Nov 20 01:11:29 MyComputer kernel: [   96.583690] FS:  00007fc021a83a80(0000) GS:ffff933230280000(0000) knlGS:0000000000000000
Nov 20 01:11:29 MyComputer kernel: [   96.583693] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Nov 20 01:11:29 MyComputer kernel: [   96.583696] CR2: 00007fc00b15b020 CR3: 000000039980c001 CR4: 00000000003606e0

After executing sudo make install I get the error:

➜  src git:(master) sudo make install
make -C /lib/modules/5.3.0-28-generic/build M=/home/dev15/akvcam/src modules_install
make[1]: Entering directory '/usr/src/linux-headers-5.3.0-28-generic'
  INSTALL /home/dev15/akvcam/src/akvcam.ko
At main.c:160:
- SSL error:02001002:system library:fopen:No such file or directory: ../crypto/bio/bss_file.c:69
- SSL error:2006D080:BIO routines:BIO_new_file:no such file: ../crypto/bio/bss_file.c:76
sign-file: certs/signing_key.pem: No such file or directory
  DEPMOD  5.3.0-28-generic
Warning: modules_install: missing 'System.map' file. Skipping depmod.
make[1]: Leaving directory '/usr/src/linux-headers-5.3.0-28-generic'

and this command sudo insmod akvcam.ko leads to this:
insmod: ERROR: could not insert module akvcam.ko: Operation not permitted

I compiled the latest kernel code and install it using modprobe command. Below is the dmesg output

Version : git commit bfe8549
OS : Ubuntu Focal
Kernel : 5.9.8

[342526.129736] [akvcam] driver.c(75): Initializing driver
[342526.129738] [akvcam] driver.c(83): Reading settings
[342526.129842] Can't read device formats
[342526.129851] Can't read device formats
[342526.129856] [akvcam] driver.c(618): No devices found

Output of the config.ini

cat /etc/akvcam/config.ini
[Cameras]
cameras/size = 2

cameras/1/type = output
cameras/1/mode = mmap, userptr, rw
cameras/1/description = Virtual Camera (output device)
cameras/1/formats = RGB24
cameras/1/videonr = 7

cameras/2/type = capture
cameras/2/mode = mmap, rw
cameras/2/description = Virtual Camera
cameras/2/formats = RGB32, RGB24
cameras/1/videonr = 9

I've been using AKVcam for a while on Fedora 30 successfully with no issues. Thanks for previous support and an awesome tool.

Upgraded Kernel to 5.4.x and this triggered an issue where dkms would apparently install the module successfully but devices in /dev were not created.

I inserted module with insmod and increased logging. Here's the dmesg output:

[20373.175286] [akvcam] driver.c(246): Error reading formats
[20373.176280] [akvcam] frame.c(394): Bitmap file name not valid
[20373.180903] [akvcam] frame.c(394): Bitmap file name not valid
[20373.181280] ------------[ cut here ]------------
[20373.181365] WARNING: CPU: 1 PID: 17688 at drivers/media/v4l2-core/v4l2-dev.c:863 __video_register_device+0x6f0/0x1030 [videodev]
[20373.181370] Modules linked in: akvcam(OE+) rfcomm md4 nls_utf8 cifs dns_resolver fscache libdes nf_conntrack_netbios_ns nf_conntrack_broadcast xt_CT ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ebtable_nat ebtable_broute ip6table_nat ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat iptable_mangle iptable_raw iptable_security nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c ip_set nfnetlink ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter cmac bnep sunrpc vfat fat squashfs zstd_decompress loop iwlmvm intel_rapl_msr intel_rapl_common x86_pkg_temp_thermal intel_powerclamp snd_hda_codec_via mac80211 snd_hda_codec_generic ledtrig_audio snd_hda_codec_hdmi coretemp snd_hda_intel snd_intel_nhlt kvm_intel snd_hda_codec libarc4 btusb snd_hda_core btrtl snd_hwdep btbcm kvm iwlwifi btintel snd_seq snd_seq_device bluetooth snd_pcm irqbypass cfg80211 iTCO_wdt iTCO_vendor_support mei_hdcp intel_cstate snd_timer ecdh_generic
[20373.181438]  intel_uncore snd mei_me intel_rapl_perf ecc pcspkr rtsx_pci_ms joydev rfkill i2c_i801 soundcore lpc_ich mei ie31200_edac memstick videodev mc ip_tables dm_crypt i915 nouveau ttm crct10dif_pclmul crc32_pclmul crc32c_intel i2c_algo_bit drm_kms_helper rtsx_pci_sdmmc mmc_core mxm_wmi drm ghash_clmulni_intel serio_raw rtsx_pci r8169 wmi video fuse [last unloaded: akvcam]
[20373.181480] CPU: 1 PID: 17688 Comm: insmod Tainted: G        W  OE     5.4.10-100.fc30.x86_64 #1
[20373.181482] Hardware name: Notebook                         W35xSTQ_370ST             /W35xSTQ_370ST             , BIOS 4.6.5 11/13/2013
[20373.181549] RIP: 0010:__video_register_device+0x6f0/0x1030 [videodev]
[20373.181553] Code: 49 89 86 80 00 00 00 48 85 c0 0f 84 5b 04 00 00 41 8b 56 2c 85 d2 0f 85 2a 04 00 00 f0 41 80 8e e8 04 00 00 01 45 31 ff eb 08 <0f> 0b 41 bf ea ff ff ff 48 8b 44 24 18 65 48 33 04 25 28 00 00 00
[20373.181555] RSP: 0018:ffffae1b412bfbc0 EFLAGS: 00010246
[20373.181557] RAX: ffff8c8013ebaf58 RBX: ffffffffc13d11c0 RCX: 0000000000000001
[20373.181559] RDX: 00000000ffffffff RSI: 0000000000000000 RDI: 0000000000000000
[20373.181560] RBP: 0000000000000001 R08: ffffffffc13d11c0 R09: 0000000000000001
[20373.181561] R10: 0000000000000000 R11: ffffd46d02a70ca0 R12: 00000000ffffffff
[20373.181562] R13: ffffffffc13c461a R14: ffff8c80e62e4800 R15: ffffffffc13d1210
[20373.181563] FS:  00007f7db01a3740(0000) GS:ffff8c80e7840000(0000) knlGS:0000000000000000
[20373.181564] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[20373.181565] CR2: 00007f7daf976000 CR3: 000000021cd66002 CR4: 00000000001606e0
[20373.181568] Call Trace:
[20373.181631]  akvcam_device_register+0x65/0x80 [akvcam]
[20373.181639]  ? 0xffffffffc02df000
[20373.181673]  akvcam_driver_register+0x29/0x80 [akvcam]
[20373.181700]  ? akvcam_settings_delete+0x72/0x80 [akvcam]
[20373.181709]  akvcam_driver_init+0xea/0x170 [akvcam]
[20373.181732]  do_one_initcall+0x46/0x1f4
[20373.181746]  ? free_unref_page_commit+0x95/0x110
[20373.181763]  ? _cond_resched+0x15/0x30
[20373.181766]  ? kmem_cache_alloc_trace+0x162/0x220
[20373.181777]  ? do_init_module+0x23/0x230
[20373.181779]  do_init_module+0x5c/0x230
[20373.181782]  load_module+0x28c9/0x2b20
[20373.181788]  ? __do_sys_init_module+0x16e/0x1a0
[20373.181789]  __do_sys_init_module+0x16e/0x1a0
[20373.181802]  do_syscall_64+0x5b/0x1a0
[20373.181809]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[20373.181814] RIP: 0033:0x7f7db02cbbbe
[20373.181816] Code: 48 8b 0d cd 32 0c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 af 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 9a 32 0c 00 f7 d8 64 89 01 48
[20373.181818] RSP: 002b:00007fff611dabb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000af
[20373.181822] RAX: ffffffffffffffda RBX: 00005569d744c8a0 RCX: 00007f7db02cbbbe
[20373.181824] RDX: 00005569d744c2a0 RSI: 000000000004ce70 RDI: 00007f7daf92a010
[20373.181825] RBP: 00007f7daf92a010 R08: 00005569d744c01a R09: 0000000000000000
[20373.181826] R10: 00005569d744c010 R11: 0000000000000246 R12: 00005569d744c2a0
[20373.181827] R13: 00005569d744c2c0 R14: 00005569d744c840 R15: 00005569d744c2a0
[20373.181830] ---[ end trace afdf6c664e0bb83f ]---
[20373.181870] [akvcam] driver.c(595): Virtual Devices:
[20373.181870] [akvcam] driver.c(596): 
[20373.181871] [akvcam] driver.c(604): Device: /dev/video0
[20373.181872] [akvcam] driver.c(605): 	Description: Virtual Camera (out)
[20373.181872] [akvcam] driver.c(608): 	Type: Output
[20373.181873] [akvcam] driver.c(613): 	Modes:
[20373.181873] [akvcam] driver.c(617): 		ReadWrite
[20373.181874] [akvcam] driver.c(626): 	User Controls: No
[20373.181875] [akvcam] driver.c(652): 	Formats:
[20373.181876] [akvcam] driver.c(661): 		RGB24 640x480 30/1 Hz
[20373.181880] [akvcam] driver.c(661): 		RGB24 160x120 30/1 Hz
[20373.181883] [akvcam] driver.c(661): 		RGB24 320x240 30/1 Hz
[20373.181886] [akvcam] driver.c(661): 		RGB24 800x600 30/1 Hz
[20373.181890] [akvcam] driver.c(661): 		RGB24 1280x720 30/1 Hz
[20373.181892] [akvcam] driver.c(661): 		RGB24 1920x1080 30/1 Hz
[20373.181893] [akvcam] driver.c(679): 	Connections:
[20373.181895] [akvcam] driver.c(687): 		/dev/video0
[20373.181896] [akvcam] driver.c(633): 
[20373.181896] [akvcam] driver.c(604): Device: /dev/video0
[20373.181897] [akvcam] driver.c(605): 	Description: Virtual Camera
[20373.181898] [akvcam] driver.c(610): 	Type: Capture
[20373.181899] [akvcam] driver.c(613): 	Modes:
[20373.181900] [akvcam] driver.c(620): 		MMap
[20373.181901] [akvcam] driver.c(623): 		UserPtr
[20373.181901] [akvcam] driver.c(628): 	User Controls: Yes
[20373.181902] [akvcam] driver.c(652): 	Formats:
[20373.181906] [akvcam] driver.c(661): 		YUY2 640x480 30/1 Hz
[20373.181910] [akvcam] driver.c(661): 		UYVY 640x480 30/1 Hz
[20373.181913] [akvcam] driver.c(661): 		YUY2 160x120 30/1 Hz
[20373.181916] [akvcam] driver.c(661): 		UYVY 160x120 30/1 Hz
[20373.181920] [akvcam] driver.c(661): 		YUY2 320x240 30/1 Hz
[20373.181924] [akvcam] driver.c(661): 		UYVY 320x240 30/1 Hz
[20373.181927] [akvcam] driver.c(661): 		YUY2 800x600 30/1 Hz
[20373.181930] [akvcam] driver.c(661): 		UYVY 800x600 30/1 Hz
[20373.181932] [akvcam] driver.c(661): 		YUY2 1280x720 30/1 Hz
[20373.181934] [akvcam] driver.c(661): 		UYVY 1280x720 30/1 Hz
[20373.181935] [akvcam] driver.c(679): 	Connections:
[20373.181937] [akvcam] driver.c(687): 		/dev/video0
[20373.181938] [akvcam] driver.c(633):

I have not modified the config.ini and the config looks good (as per #6).