transcode

I had this great movie (from Ron Fedkiw), which, unfortunately was encoded with the MPEG-4 Video High Speed Compressor (fourcc MPG4).

Because I wanted to change the codec, I tried to install transcode.

If, during compilation of transcode, you get an error like this:

/usr/bin/nasm -g -felf -o fdct_mmx.o fdct_mmx.s
fdct_mmx.s:394: error: operation size not specified

you should just edit the file fdct_mmx.s, and change line 394 from

punpcklwd mm5,  [INP+8] ; mm5 =  5 7 4 6

to

punpcklwd mm5,  dword [INP+8] ; mm5 =  5 7 4 6

</offtopic>

Anyways, I wanted to transcode the AVI-file from MPG4 to DIVX.
So I tried:

transcode -i input.avi -x mplayer -y divx4 -o output.avi

However, strangely, the image gets “sort-of” flipped.
One frame from the original video:

Original movie

And the same frame from the converted video:

Converted movie

Note, how the glass is flipped upside down, but the colors aren’t!

The solution is to use the -V option to transcode to “use YV12/I420 as internal video codec” (from the manpage). So, just type:

transcode -i input.avi -x mplayer -y divx4 -o output.avi -V

and everything will be fine…!

Friday, February 21st, 2003 Computing

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