[FFmpeg-devel] [PATCH 6/7] mxfdec: set sample aspect ratio for uncomp rec601
Philip de Nier
philipn at rd.bbc.co.uk
Wed Feb 29 13:56:30 CET 2012
On 28/02/12 18:36, Baptiste Coudurier wrote:
> On 02/28/2012 06:16 AM, Philip de Nier wrote:
> This one I'm hesitating. The problem is that setting sample aspect ratio
> to these values will break
> the rule width/height == dar/par which is expected in many places.
> I believe sample aspect ratio should follow the rule and another field
> like clean aperture should be exported.
> Furthermore, this assume the source is analog and not digital.
> Michael ?
Thanks for reviewing and applying the patches.
My 2 cents on sample aspect ratio:
I guess that is MPEG's rule on SAR, DAR and picture dimensions and if
FFmpeg is following that then sample_aspect_ratio is different from the
one I was assuming.
A practical issue is that if I run "ffmpeg -i unc_625_16x9.mxf test.mov"
and the mxf demuxer does not set the sample_aspect_ratio to 118/81, then
the quicktime file has the incorrect (i.e. not h_spacing=118,
v_spacing=81) pixel aspect ratio in the pasp tag.
Not sure I understand the comment about analog versus digital as Rec.
601 deals with digital television
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