[MPlayer-users] about sound frequencies ???....

charlie noisilysilent at netscape.net
Thu Jul 25 17:23:02 CEST 2002

hi all,

this mail has no real point with mplayer, but as lots of you try make 
create svcd's, this might interest those ;-)
ok, here's the problem:
i had the following divx movie:
video: 25 fps 720*320
audio: 24 kHz, 64 kb/s
and wanted to make a svcd from this.
to abide svcd format, i did the following:

 > mkfifo stream.yuv
 > mplayer -ao null -vo yuv4mpeg -vop expand=720:404:0:42:0 

to make it a pure 16/9 movie, addind black borders.
then, lets play with mjpegtools:

 > yuvdenoise -b 0,42,720,446 < stream.yuv | yuvscaler -O SVCD -M 
BICUBIC | mpeg2enc -S 760 -f 4 -F 3 -q 7 -I 0 -V 300 -a 3 -o video.m2v

that was for the video. After 23 hours of processing, i finaly got a 
pretty good video stream ;-)

next, for the audio stream:

 > mplayer -vo null -ao pcm /mnt/dvd/devils_advocate.avi
 > mp2enc -V -o audio.mp2 < audiodump.wav

which gave me a 44100 Hz, 224 kb/s stereo audio stream.

The problem went when multiplexing:
 > mplex -f 4 video.m2v audio.mp2 -o devils_advocate.mpg

i finaly got a movie but there is a problem with the sound. minutes 
after minutes, there is a delay appearing during the movie :(
at the beginning, very nice, but at the end, several seconds !

i thought the problem was due to sound frequency, from 24000 to 44100 
Hz. i tried encodeing sound to 48000Hz (though not sure it is SVCD 
compliant, but the problem is still the same)
if anyone of you has a slight opinion on the subject, thanks for helping ;-)


More information about the MPlayer-users mailing list