[FFmpeg-devel] [PATCH3/3] avfilter YUV aligment 32 bytesaligment for Y only and 16 bytes for UV.

[Richard Buteau]

> -----Original Message-----
> From: ffmpeg-devel-bounces at mplayerhq.hu [mailto:ffmpeg-devel-
> bounces at mplayerhq.hu] On Behalf Of Bobby Bingham
> Sent: Tuesday, September 21, 2010 5:28 PM
> To: ffmpeg-devel at mplayerhq.hu
> Subject: Re: [FFmpeg-devel] [PATCH3/3] avfilter YUV aligment 32
> bytesaligment for Y only and 16 bytes for UV.
> 
> On Tue, 21 Sep 2010 20:43:30 +0100
> M?ns Rullg?rd <mans at mansr.com> wrote:
> 
> > "Richard Buteau" <rbuteau at rgbnetworks.com> writes:
> >
> > >> "Richard Buteau" <rbuteau at rgbnetworks.com> writes:
> > >>
> > >>> Hi all,
> > >>> Some encoder don't support linesize[] that aren't multiple. As an
> > >>> example they expect 720/360/360 for yuv image or 732/368/368.
> > >>> the avfilter align all linesize on 16 byte, this make a yuv
> 720/368/368.
> > >>> 720 isn't a multiple of 368.
> > >>> I added alignment on 32bytes for Y only so it's always
> 732/368/368
> > >>
> > >> Why?  Nothing requires alignment greater than 16.  If something
> did,
> > >> this patch would be the wrong way to fix it.
> > >
> > > The other option to preserve 2:1 ratio between linesize[0] and
> > > linesize[1]/linesize[2]
> >
> > What makes you believe such a requirement exists?
> >
> > Also, don't top-post and do quote properly.
> >
> 
> I do remember seeing this comment in libavcodec/utils.c in
> avcodec_default_get_buffer:
> 
> // NOTE: do not align linesizes individually, this breaks e.g.
> assumptions
> // that linesize[0] == 2*linesize[1] in the MPEG-encoder for 4:2:2
> 
> Nothing in libavfilter should be making this assumption, but I can't be
> sure about other code.
Does that count as a requirement?

> 
> --
> Bobby Bingham
> ??????????????????????
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