[Libav-user] Visual corruption when decoding H264

[Lovelett, Ryan A.]

> I forgot to mention that I am using FFMPEG through OpenCV. Since an earlier
> version of FFMPEG was giving problems while decoding H.264 based RTSP
> stream, I updated to the latest FFMPEG version (recompiled it by self) and
> it worked fine. Not sure if this serves your purpose.
> 
> --
> Regards,
> Saurabh Gandhi
> 
> 
> 
> 
> 
> On Thu, Jun 2, 2011 at 4:47 AM, STenyaK <stenyak at gmail.com <http://ffmpeg.org/mailman/listinfo/libav-user> > wrote:
> 
>> Thanks for the reply.
>> 
>> Apart from updating to latest ffmpeg version, did you do anything else
>> for it to work? I'm still experiencing the same visual glitches.
>> 
>> On Mon, May 30, 2011 at 11:53, Saurabh Gandhi <saurabhg84 at gmail.com <http://ffmpeg.org/mailman/listinfo/libav-user> >
>> wrote:
>> > Are you using the latest version of FFMPEG. We had similar issues here
>> which
>> > got resolved by updating to the latest version
>> >
>> > --
>> > Regards,
>> > Saurabh Gandhi
>> >
>> >
>> >
>> >
>> > On Mon, May 30, 2011 at 2:30 AM, STenyaK <stenyak at gmail.com <http://ffmpeg.org/mailman/listinfo/libav-user> > wrote:
>> >>
>> >> Hello,
>> >> I'm having troubles trying to decode H264 by feeding
>> >> avcodec_decode_video with data coming from an RTP stream. I'm going to
>> >> describe the visual result, maybe it can help find out where the
>> >> problem lies:
>> >>
>> >> The image is perfect in the first frame of the stream. From that point
>> >> on, it looks as if only p-frames got decoded: the image begins to get
>> >> progressively more blurred with each frame whenever something in the
>> >> image changes or moves position.
>> >> Every 10-20 seconds of stream, the image starts a quick reconstruction
>> >> process. the image gets corrected (visual trails removed) in a sweep
>> >> from left to right that takes about half a second or two.
>> >>
>> >> Reading the same RTP stream with other software (also based on ffmpeg)
>> >> works correctly, with no visual corruption at all, so I must be
>> >> missing something.
>> >>
>> >> Does anyone have any idea what the problem could stem from? Any
>> >> pointers are appreciated.
>> >>
>> >> Thanks in advance.
>> >>
>> >> --
>> >> Saludos,
>> >>      Bruno González
>> >>
>> >> _______________________________________________
>> >> Jabber: stenyak AT gmail.com
>> >> http://www.stenyak.com <http://www.stenyak.com/> 
>> >> _______________________________________________
>> >> Libav-user mailing list
>> >> Libav-user at ffmpeg.org <http://ffmpeg.org/mailman/listinfo/libav-user> 
>> >> http://ffmpeg.org/mailman/listinfo/libav-user
>> >
>> >
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>> >
>> >
>> 
>> 
>> 
>> --
>> Saludos,
>>      Bruno González
>> 
>> _______________________________________________
>> Jabber: stenyak AT gmail.com
>> http://www.stenyak.com <http://www.stenyak.com/> 
>> _______________________________________________
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> 
> 
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> 

Hi,
I'm having the exact same issue as you when decoding x264 with the avcodec_decode_video2 function. I only get 1/3 of the frames, the video degrades progressively around the areas where motion occurs 


 
and then suddenly fixes itself and then slowly degrades again and so on.
I was using the Jun 3 windows dlls built here:http://ffmpeg.zeranoe.com/builds/. I also posted this problem on the Zeranoe forum: http://ffmpeg.zeranoe.com/forum/viewtopic.php?f=15&t=54


 
but it's pretty quiet over there. I have posted there some of the code I'm using to show the problem. In particular, from the log that gets logged when the code runs (posted over there)
you'd see that the pts of the last packet is 1/3 of the duration. I thought that I was missing some operation after calling avcodec_decode_video2, but I guess the problem is something else.

Thanks,
Matt E
Btw, sorry if the formatting comes out wrong because this is my first time posting to a mailing list.
________________________________

 
Matt,
My guess is that the frames that are working are the movie's I frames, the ones that are degraded are the P frames. Or at least that is the case in my scenario. The codec that mine is having an issue with: CODEC_ID_H264 (H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10). Using build ffmpeg-git-39dbe9b from Zeranoe's builds.
 
I am having the same issue, only with seeking. That is to say, if I continuously decode 'av_read_frame' from start to finish the video decodes just fine. If I seek to a frame, and then decode the video quality degrades frame by frame.
 
Suggestions welcome.
 
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