Fwd: Audio and AVI output on the userspace capture tool

[Rodrigo Exterckötter Tjäder]

Hello.

I have added two features to the userspace capture program: audio
capture, using the --ao option to select what file it will be dumped
on, and AVI output, using --avi, which allows you to output both audio
and video to a single AVI file.

The AVI output feature is particularly useful if you want to pipe the
capture to an encoder, as doing it with two named fifo often leads to
the capture program blocking when writing to the video fifo while the
encoding program is blocked reading on the audio fifo, or vice-versa.

I have attached the patches generated by git format-patch.

[markus.ga...@advantecgmbh.de]

Hello,
this post http://forum.easycap.co.uk/index.php?topic=622.0 describes how an user captured data via directx modules. I'm sure there are similar tools and libraries for linux distros available.

Maybe it gives idea to handle the streamed data.

Greets

[vfra...@tiscali.it]

Hello, I tested these patches and I found a bug.
When you capture from pal 25fps source, there is an audio-video desync due to incorrect parameters in avi header.

To fix change line 721 in somagic-capture.c
from
            bufdw[7] = 30; // dwRate
to
            bufdw[7] = 25; // dwRate

and change line 763 in somagic-capture.c
from
            bufdw[7] = 25000; // dwRate
to
            bufdw[7] = 24000; // dwRate

Now audio-video are in sync with continuous flow of good frames.

Instead I noticed if during capture there are some bad frames (VHS or DTT/SAT receiver),
audio in avi file output is no longer synchronized differently from windows (capture from potplayer always in sync with bad frames).