[MPlayer-users] incorrect playing rate with dxr3 sound driver
Jean-Louis Debert
JLD at rsd-intl.com
Fri May 31 07:11:01 CEST 2002
Hi,
I have an .avi file which was encoded at 24KHz (stereo).
Now I want to play the .avi on the TV set, using the TV
and sound output of my dxr3 card. So I use the following
command line:
$ mplayer -vo dxr3 -ao oss:/dev/em8300_ma-0 RH2.avi
Playing starts ... 2x too fast for _both_ audio _and_ video.
Now the funny thing is, when I use the normal oss driver
for my sound card (not specifying -ao at all) playing is
absolutely correct ...
After some searching in TFM, I found this (in file DXR3 in the docs):
-aop list=resample:fout=xxxxx If samplerate is below 44100Hz, select
either 44100 or 48000 depending on
which which one matches closest. I.e.
if the movie uses 22050 use 44100 as
44100 / 2 = 22050, if it's 24000 use
48000 as 48000 / 2 = 24000 and so on.
So, knowing that the sound in the file was encoded at 24KHz, I added
-aop list=resample:fout=48000 and it works correctly (for both
audio and video).
Now I am wondering why this is not done automagically ??? I mean,
whenever you get a file (or worse, a stream) over the Internet,
you seldom know _beforehand_ the way it was encoded, so you cannot
set a useful parameter in a script or otherwise... you have first
to run mplayer and parse the log to know.
Whereas at audio driver setup time, I believe that the headers
(if any) are already parsed, so the video and audio parameters
are already known, so the driver _could_ be setup automatically
using the rule above. By the way, processing is okay for the
oss _soundcard_ driver, so why not for the dxr3 one ?
Am I correct in believing this ???
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