[FFmpeg-devel] H.264 + PAFF: BBC HD recording shows extreme interlacing artefacts

Måns Rullgård mans
Sun Oct 28 21:20:24 CET 2007

Michael Niedermayer <michaelni at gmx.at> writes:

> Hi
> On Sun, Oct 28, 2007 at 07:46:07PM +0100, Reinhard Nissl wrote:
>> Hi,
>> Michael Niedermayer schrieb:
>> >>> no, there is no problem with decoding, the problem is in the yv12->rgb
>> >>> convertion, the fields have to be converted seperately not like a frame
>> Is this a general rule, 
> yes
>> i. e. should this also be the case for MPEG2 frames when flag
>> "interlaced_frame" is set?
> yes in theory, in practice IIRC these flags are often set incorrectly by
> the encoder

The progressive_sequence flag in the MPEG2 sequence extension header
is often misleadingly set to 0 due to soft telecine being used.  I say
misleadingly, not incorrectly, since the spec allows any picture
structure when this flag is 0.

The flags in the picture header and picture coding extension are
generally more reliable.

M?ns Rullg?rd
mans at mansr.com

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