[FFmpeg-devel] [BUG] h264 picture reordering fails

Haruhiko Yamagata h.yamagata
Sun May 31 10:51:33 CEST 2009

> On Sat, May 30, 2009, Haruhiko Yamagata wrote:
>>> On Sat, May 30, 2009 at 07:34:32PM +0900, Haruhiko Yamagata wrote:
>>>> I found picture reordering fails in
>>>> http://x264.nl/h.264.samples/premiere-paff.ts
>>>> Outputted pictures have POC {-4, -2, 4, 0, 2, 6}.
>>>> Are negative POCs allowed?
>>>> If yes, zero as POC is valid as well.
>>> about POCs, IIRC the spec requires POC=0 to be true and only true for
>>> IDR pictures, but i might misremember (would have to check the spec)
>>> What i do know is that the POC or frame number == 0 rules in the spec
>>> are not followed by some encoders.
>> Yes, I think POC=0 means IDR. In that case, negative values as POC are
>> not allowed.
On Sun, May 31, 2009, fenrir wrote:
> This point has been discusses on the JVT mailing list, it was said that
> negative POC are valids, they just mean that the picture has to be displayed
> before the IDR.

OK, I understand.
Then negative POC should typically be -2, while longer reference chains are theoretically possible.

Obviously it is not the case with mine. The frame with POC 0 happens to be a B frame.

Best regards,
Haruhiko Yamagata

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