makazone / videoexport Goto Github PK

This is an iOS Swift based project that is intended to show how various video formats and orientations can be read and exported for maximum compatibility across clients and reduced size.

The following criteria was used for export:

1. Dimensions reduced to no greater than 512 x 288 (16:9) or 480 x 360 (4:3)
2. Rotation (preferred transform) of container set to 0 degrees (CGAffineTransformIdentity).
3. Video profile level set to AVVideoProfileLevelH264Baseline30 ([email protected])
4. Video bitrate reduced to average of 725,000 bps
5. MP4 container

Navigate to the folder where you downloaded the project (Ex: VideoExport-master) and execute

pod install

Assumes that CocoaPods is installed on your system.

Some videos cannot be processed on the simulator, but will work fine on a real device.

This is an Xcode bug that has been documented in the following article: Using a video composition to process certain videos causes an Xcode simulator hang

A bug report has been filed with Apple. A project demonstrating the bug can be found at: GitHub VideoCompositionSimulatorBug

There is no known workaround.

There exists a bug on the simulator wherein a CMTime structure can get corrupted when it is passed from Swift to Objective-C. It occurs only on the iPhone 4S and iPhone 5 configurations. The bug has been documented in the article: Xcode simulator bug with Swift to Objective-C call passing CMTime structure

A bug report has been filed with Apple. A project demonstrating the bug can be found at: GitHub CMTimeBug

A workaround exists and has been implemented in the method getVideoComposition() in ViewController.swift.

There is extensive details about the project including how I established the criteria to be used in the file README.h

The Table of Contents of that file includes:

Overview

Criteria Discussion

• Support for MPMoviePlayerController
• Support for Dropbox
• Android Support
• Bitrate considerations
• Container

Meeting project criteria

• AVAssetExportSession
• AVAssetReader/AVAssetWriter
• SDAVAssetExportSession

Misc. Project Notes

Portrait Example

Preferred transform

Contrasting preferred transform with video composition transform

• Method 1
• Method 2
• Comparison of methods

Additional References

• General
• Temp directory
• Adding & Retrieving Metadata
• MPMoviePlayerController
• UIRequiredDeviceCapabilities
• Reducing file size
• Video settings