[FFmpeg-devel] [PATCH] AVCHD/H.264 parser: determination of frame type, question about timestamps

David DeHaven dave
Thu Jan 29 21:12:53 CET 2009

On Jan 29, 2009, at 9:56 AM, Ivan Schreter wrote:

> David DeHaven wrote:
>> Any interest in clips from the Hauppauge HD-PVR? I can get samples
>> captured in 480i, 480p, 720p and 1080i. I think I have a 576i clip
>> somewhere from a PAL source, if I dig out my signal generator or  
>> maybe
>> the VCR with PAL/SECAM output I could produce another one if needed.
> It will surely not hurt to have the samples :-)
>> The HD-PVR is based on a chip from Ambarella that's also used in  
>> cameras. The firmware is different (obviously) but I think the  
>> streams
>> are similar to what the cameras spit out, MPEG TS with H.264 video  
>> and
>> either AAC or AC3 audio. AC3 is either 2 channel stereo or whatever
>> comes in via S/PDIF.
>> I figure more samples might help shed some light on the issue...  
>> and I
>> do have a vested interest in getting it working properly.
> The cause of the issues in processing of interlaced video seems to be
> clear, the solution not.
> I've a first version of a patch to handle progressive video keyframes
> correctly, but only after recoding from mpegts to other format (maybe
> there is a bug in seeking in mpegts?).
> What was your experience when watching the recorded files when decoded
> via ffmpeg (especially, after seeking)? What bugs do you see there?

I'm going to build up and run a test matrix and will post the results  
when ready. That will take some time...

In short, playing in MPlayer:
interlaced formats don't play when using -demuxer lavf and plays at  
1/2 video rate (A/V goes out of sync VERY quickly!) with -demuxer mpegts
progressive formats play just fine using -demuxer lavf, A/V sync  
seems... sloppy with -demuxer mpegts especially when seeking around in  
the stream

Transcoding of both interlaced and progressive seem to be OK with a  
patch that modifies the -vsync behaviour (I think someone posted a  
similar patch late last year).
I cannot remux interlaced streams into mov/mp4 container, it complains  
about non-monotone timestamps (new == old) and bails.
Remuxing progressive streams seems to work. The results don't play  
back in QuickTime Player but they play just fine in MPlayer and VLC  
(probably a deficiency in QT... not the first).


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