Invalid track id - no matter what - while creating a clip about mp4v2 HOT 10 CLOSED

Possibly some issue with your input file? Here is a source code that works for 
me to retrieve track-id on an 
existing mp4 file:

#include <stdio.h>
#include <mp4v2/mp4v2.h>

int main( int argc, char** argv )
{
    if( argc != 2 ) {
        printf( "usage: %s file.mp4\n", argv[0] );
        return 1;
    }

    /* open file for modification */
    MP4FileHandle file = MP4Modify( argv[1], MP4_DETAILS_ERROR, 0 );
    if( file == MP4_INVALID_FILE_HANDLE ) {
        printf( "MP4Modify failed\n" );
        return 1;
    }

    /* fetch track id of first track */
    MP4TrackId tid = MP4FindTrackId( file, 0, NULL, 0 );
    if( tid == MP4_INVALID_TRACK_ID )
        printf( "tid=%u (FAILED)\n", tid );
    else
        printf( "tid=%u (SUCCESS)\n", tid );

    MP4Close( file );
    return 0;
}

[deleted comment]

Is your file already hinted? If not, why are you trying to get the hint track 
reference id? 
You are passing the track id of your audio track to a function that want the 
track id of 
an hint track.

If you don't need any hinting you can just pass MP4_INVALID_TRACK_ID as the 
hint 
track Id in MP4CopyTrack()

[deleted comment]

[deleted comment]

Well if you don't know what hinted means you can just ignore it. And all your 
duration/time convention stuff is just weird. The edit list times must be in 
the movie 
timescale unit, not in the track one.
And wouldn't be easier to just copy the samples you need to the new file 
instead of 
using an edit list?

[deleted comment]

I'm going to close this issue because it's not an issue. Sorry but this is not 
the place to seek tutorial styled help. 
It's for bugs, RFEs and such. (This is not meant to sound disparaging).

[deleted comment]

MP4CopyTrack() with applyEdits semantics to create a clip from a larger source 
works for me. Again no issue 
here. I know of no place that offers free tutorial help; in my opinion your 
best bet is to find open-source 
programs that use mp4v2 and see how they use edits to create a clip; I'm not 
aware of any that do. Sorry.