[FFmpeg-devel] [RFC] Error concealment for B-frames/fixing issue 824

Baptiste Coudurier baptiste.coudurier
Tue May 5 23:08:33 CEST 2009

Baptiste Coudurier wrote:
> On Fri, Apr 10, 2009 at 06:50:08PM -0700, Baptiste Coudurier wrote:
>> Hi Reimar,
>> On 4/9/2009 3:13 PM, Reimar D?ffinger wrote:
>>> On Thu, Apr 09, 2009 at 10:52:32PM +0200, Michael Niedermayer wrote:
>>>> there are 2 very seperate things
>>>> 1. errors
>>>> 2. b frames without reference frames after seeking
>>>> normal users dont want to see randomly trashed frames after seeking
>>>> in undamged files
>>> I think I agree... Is there a counter somewhere that could be used to
>>> find out which frame in the GOP we are at?
>> Yes temp_ref in pic structure.
>>> Some options I can think of:
>>> 1) change code to not skip a B-frame if it is the second frame in a closed GOP
>>> 2) only skip B-frames if they directly follow the first I-frame of a non-closed GOP
>>> 3) (without really knowing what "broken link" means) only skip B-frames if "broken
>>> link" is set
>> From what I understand, broken link explicitly state that the 2 next b
>> frames cannot be decoded because the stream was cut at the preceding I
>> frame, therefore the original reference I frame is no more available.
>> And I think your strategy should be ok :)
> Here is another attempt.
> It will decodes them only is closed gop is set.
> I got a sample with open gop and B frames before the I frame, it
> works, also, decoding them anyway does not crash when dummy picture is
> allocated some block are gray.
> Patch attached.

New patch attached, more correct.

Baptiste COUDURIER                              GnuPG Key Id: 0x5C1ABAAA
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FFmpeg maintainer                                  http://www.ffmpeg.org
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