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

[Måns Rullgård]

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