[FFmpeg-devel] Frame dropping with mpeg2 ffmpeg decode in Handbrake

[Yuan Yeow Leow]

I'm not sure if this is the right forum to ask this, but here goes.
I'm currently implementing MPEG2 DXVA decode in Handbrake which uses
ffmpeg. The DXVA decode will make use of ffmpeg for decoding. We did this
by switching the default MPEG2 decoder from libmpeg to ffmpeg.

I found that frames were being dropped in many MPEG2 VOB files for hardware
decoding. After switching Handbrake to using software decode with ffmpeg, I
found the frames were being dropped with software decode as well.
I'm not certain whether this is a problem with Handbrake integration with
ffmpeg itself, or whether the problem lies with ffmpeg.
However, ffmpeg function calls to get the PTS return AV_NOPTS_VALUE for
many frames.
Handbrake replaced this frames with the PTS value of the previous frame,
but later dropped the frames further down the pipeline because they're
treated as duplicate frames.
I understand it's most likely not a problem with ffmpeg. But perhaps I was
hoping that similar errors have turned up in the past which might provide a
clue as to how to resolve this problem.
I'm wondering if anyone know any clues as to how to resolve this issue?
Thank you.

Best regards
Leow Yuan Yeow