[MPlayer-dev-eng] enhancement for yuv4mpeg output driver
D Richard Felker III
dalias at aerifal.cx
Wed Jan 19 22:58:17 CET 2005
On Wed, Jan 19, 2005 at 01:31:26PM -0800, Trent Piepho wrote:
> > > mplayer has the wrong idea of the pixel aspect isself, for example, a 720x480
> > > 4:3 NTSC DVD should be scaled to 720x528, not 720x540. So I added an 'aspect'
> > The scaled size isn't placed in the yuv4mpeg2 header so I think that's
> > a different issue (when playing the movie on the computer for example)
> > but you're right, the wrong thing is being done.
> > The SAR (sample aspect ratio) placed in the yuv4mpeg2 header
> > should be 10:11 for "NTSC", and 59:54 for "PAL" (or 40:33 and 118:81
> > for 16:9 movies in the two video systems). Hmmm, but when you're
> > decoding a SVCD the SAR is 15:11 and 59:36 respectively). Does the
> > yuv4mpeg module have sufficient knowledge to emit the correct 'A'
> > tag? If not then "0:0" is appropriate.
> I use mplayer's idea of the correct scaled size of the video to guess the
> sample aspect ratio. In some cases this works, a 704x480 4:3 DVD will have
> a SAR of 10:11, a HDTV capture will have a SAR of 1:1, etc. In some cases
> it is sligtly off, due to pixel rounding. In others it is off by a bit more,
> because mplayer has the wrong idea of the SAR itself.
yes, using picture aspect ratio instead of sample aspect ratio is very
very stupid... if/when mplayer is completely overhauled/replaced, it
will use sample aspect instead.
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