[FFmpeg-user] ffmpeg libx264 VBR and CBR output generates different POC, possible bug

[Maxim Levkov]

Hello,

I've been doing some experimentation and discovered that output for libx264
CBR with CBR HRD, not capped VBR, has different Picture Order Count, than
VBR output with VBR HRD. I believe it is a bug, unless I'm missing
something. The output is generated with ffmpeg libx264 muxed into mp4
container, with accompanying AAC-LC audio, from same avi source.

It would be great if someone can tell me if they have experienced the same
thing. I'm tempted to file a bug.

>From what I understand POC for H.264 VBR and CBR should not be different,
only payload is different.

I thought that this had something to do with a reporting error on input for
"non-interleaved" avi, but after numerous tests with other "containers",
I've come to a same result, which suggests that it is either a bug, or an
inherent feature. The "feature" part does not sit well, because "muxing"
these files down the stream produces completely different time positions
for any one point in the video.

I'm not sure of a command line that can "force" insertion of "aud' and
"poc" and any other command to make sure "tbn, tbc, tbr" stay the same.

Thank you for your feedback.

Sidepoint: Where do I file a bug?

Best Regards,
Maxim