--- Ronald Bultje <[EMAIL PROTECTED]> wrote:
> Hi Brian,
>
> On Sun, 2003-01-05 at 16:28, [EMAIL PROTECTED] wrote:
> > When I use lavrec to create a movtar file, and then try to extract the
> > audio from the movtar file with lav2wav, it comes out "gurgly". By
> > gurgly, imagine the filter a special effects man would use to make you
> > believe somebody was talking under water.
>
> Sounds like... Your sampling rate is a bit weird? Does lavinfo report
> the sampling rate correctly?
It's a weird issue with movtar. The sound is almost as if when recording
to movtar, every other sample is dropped, and the remaining set is
duplicated to fill in the gaps. Since both avi and qt work correctly,
there is a workaround for the problem.
> ... Quicktime is said to be
> directly readable while recording and to record over 2 GB (64bit
> addressing). So quicktime is probably a good bet here.
At least with the qt4linux distributed with mjpegtools 1.6.0, it was
impossible to access the qt file for any mjpeg purpose until after lavrec
had finished recording and closed out the file. Yes, Linux could read the
file from disk, but any attempt to access the qt file as a video file
would fail. Even mplayer would not access it, and mplayer seems to read
just about anything. Additionally, any problem with recording ("ring
buffer overflow", machine crash, etc.) during the session will almost
always result in a inaccessable qt file sitting on disk taking up space.
I learned this one the hard way when I lost a couple recordings (95+%
complete) to this misfeature of qt files. My solution was to switch to
recording to avi files.
With avi's they still are not playable while being recorded to, but as a
new one is created every 2G (by default) all the previous closed avi's are
completely usable as video files. Also, when something buggers lavrec/the
machine during a recording, it's trivial to use dd to copy a valid avi
header onto the front of the bogus file and make it work enough to be
useful. I know this one from experience as well, I had to recover one avi
when my recording machine buggered on me at the last moment during a
recording.
I'd suggest that Brian avoid qt's due to the risk of losing everything due
to a tiny little glitch at the last moment, and instead just use avi's.
If you give lavrec a filename with a %d (e.g., %02d for two digits zero
filled) expansion in it, lavrec will make multiple 2G files for you as it
goes along, all automatically.
Rich
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