[FFmpeg-devel] mpegvideo : interlaced_frame with picture_structure == PICT_FRAME

Michael Niedermayer michaelni at gmx.at
Tue Jan 6 00:35:31 CET 2015

On Mon, Jan 05, 2015 at 03:17:32PM -0500, Vanista Herion wrote:
> Some MPEG 2 video will give bad interlacing information in AVFrame. If the
> parameters are used by a deinterlace filter such as yadif, frames will be
> processed needlessly and impair the quality.
> By reviewing the code in mpegvideo.c which sets the interlaced_frame
> and top_field_first, I noticed that picture_structure is not considered
> whereas it probably supersedes everything else. The H.262 specification is
> not very clear on that but in the case of this sample, the stream is
> definitely progressive, picture_structure is equal to 3 (Frame picture) and
> top_field_first alternates true and false.
> The result is that frames come out reported as tff, bff and progressive,
> cycling at every frame.
> I propose a simple patch to set interlaced_frame to false when
> picture_structure is equal to PICT_FRAME.

fixed differently, that is by detecting telecined content in yadif


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

When the tyrant has disposed of foreign enemies by conquest or treaty, and
there is nothing more to fear from them, then he is always stirring up
some war or other, in order that the people may require a leader. -- Plato
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