[FFmpeg-devel] [PATCH]: Fix decoding of mpegts streams with h264 video that does *NOT* have b frames

Mike Scheutzow mike.scheutzow at alcatel-lucent.com
Fri Apr 22 15:21:42 CEST 2011

I'm an idiot, because both my comments yesterday were wrong.

Tony Strauss wrote:
> On Thu, Apr 21, 2011 at 3:34 PM, Mike Scheutzow 
> mike.scheutzow wrote:
>> Tony Strauss wrote:
>>>> You can reproduce by running: ffprobe -loglevel debug
>>>> -show_packets 720.no_b_frames.ts
>> This .ts file does not look valid to me. I find no start codes in
>> the video elementary stream. As far as I know, H264 should be using
>> Annex-B format within a transport stream.

Your test file does have start codes.

>> Does the video contain P-frames? If it contains P-frames, then pts
>> != dts. Please post a link to a valid file so we can see.
> Interesting.  I really don't know much about video encoding, but this
>  surprises me.  Certainly a patched ffprobe shows pts == dts for 
> clip.no_bframes.ts (and this does have p frames, since refs=1).  Why 
> would the presence of p-frames change pts == dts?  Since p-frames
> only depend on an earlier frame, can't they be presented as soon as
> they're decoded?

Again, you're right.

I'm sorry I wasted your time. Now I feel obligated to review your patch.

I'll try to look at it this weekend.

Mike Scheutzow

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