[FFmpeg-user] prevent clean aperture value cropping

[Kieran O Leary]

Hi

I do think this is a bug, as FFmpeg did not previously behave this
way. I made an ffv1/mkv from the test video provided, then reversed
that back to v210/mov. I got matching md5 values when decoding the
video streams, but the width values appear to be hardcoded to the clap
value. I used mediatrace within mediainfo as well and could not find
any trace of '720' in the FFv1 or 'reversed' v210. For example, from
the original source video:

3548AF8    Track width:                         720.000

3548C3E        Width:                           720 (0x02D0)

3548CA8         apertureWidth_N:                703 (0x000002BF)

3548CAC         apertureWidth_D:                1 (0x00000001)

3548DFC     cleanApertureWidth:                 787.000

3548E10     productionApertureWidth:            787.000

3548E24     encodedApertureWidth:               720.000


and from the reversed mov (source video -> ffv1.mkv -> back to v210.mov)

4C3EE8    Track width:                         702.000

34C402E        Width:                           702 (0x02BE)

34C4098         apertureWidth_N:                702 (0x000002BE)

34C409C         apertureWidth_D:                1 (0x00000001)

34C41EC     cleanApertureWidth:                 767.000

34C4200     productionApertureWidth:            767.000

34C4214     encodedApertureWidth:               702.000

Best,

Kieran