Hi,
I noticed that my transcoded mpeg looks distorted -- all people are having
long faces. I'm wondering how to fix. This is what I did:
- The frame size of the avi source is 640x272
- I pad the border with -Y -104,-32,-104,-32 to make it 704 x 480: [1]
$ transcode -i "test_tx.avi" -Y -104,-32,-104,-32 --export_asr 2 -y
mpeg2enc,ffmpeg ...
[transcode] V: import frame | 640x272 2.35:1
[transcode] V: clip frame (->) | 704x480
This is what I used to do. Don't know if they were NOK previously, but today,
I noticed the "long face" problem, and I looked further into the problem.
When the avi is played in mplayer, the mplayer log said:
VDec: vo config request - 640 x 272 (preferred colorspace: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 2.35:1 - prescaling to correct movie aspect.
VO: [xvidix] 640x272 => 640x272 Planar YV12
^^^^^^^
This is normal. When the transcoded mpeg is played in mplayer, the mplayer
log said:
VDec: vo config request - 704 x 480 (preferred colorspace: Planar YV12)
VDec: using Planar YV12 as output csp (no 0)
Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
VO: [xvidix] 704x480 => 704x528 Planar YV12
^^^^^^^
What ^^^ underlined are what actual pixels mplayer used for the displace.
As we can see, when playing the 1:1 avi, mplayer plays the video height as
is; whereas when playing the 4:3 mpeg, mplayer need to stretch the height
to compensate the 4:3 aspect ratio. This what mplayer always has been
doing to the 4:3 aspect ratio sources. I think that's the reason that
people are having long faces in my mpeg file.
Am I right about the above analysis? What the right way to do/fix is such
situation?
thanks
PS.
[1], full actual command line
transcode -i "test_tx.avi" --ext none,none -Y -104,-32,-104,-32 --export_asr
2 -M 4 -o "test_tx-.m2v" -m "test_tx-.mpa" --video_max_bitrate 3600 -y
mpeg2enc,ffmpeg -F 8,'-q 8 -b 3600 -S 4400' --pulldown -N 0x2000 -E 48000,16,2
-b 192 -s2
--
Tong (remove underscore(s) to reply)
http://xpt.sourceforge.net/
