Re: No Sound Through Video Capture Card
Am 08/02/2010 01:25 AM, schrieb Scarletdown:
> I'm building a Linux system specifically for video capture in prep for
> yet another video games review site I want to attempt. She is running
> Debian Sid with Enlightenment as her desktop.
>
> I am having a helluva time trying to get things working properly.
> First of all, I just installed my old PCTV (bt878 based) TV tuner that
> used to work fine for me years ago. On this, I am getting video fine,
> but not getting any sound through the card I tried connecting the
> speakers directly to the card's line out and also tried running a
> patch cable from line out to the sound card's line in and then
> connecting the speakers to the sound card. Both configurations
> resulted in no sound at all.
>
> Additionally, XAWTV for some reason is not saving my settings when I
> exit. Why would that be? Also, captured video when played back
> through vlc as well as when played online, is tearing pretty bad
> (looks okay when played on the old TV though). It is also running a
> little too fast. I recorded at 24fps, thinking that was the NTSC
> standard for video. Was that an incorrect guess? Here is a clip,
> captured from a Wii game showing the tearing and slightly too fast
> playback (don't laugh, this is being done for the amusement of my
> young neices and nephews next time I go visit them. :p
>
Having done exactly what you are describing with A/V output from VJing
machines using a BT878 myself, I'd suppose you:
- just forget XAWTV for capturing
- get mencoder, ffmpeg and probably some H264 stuff like GPAC for web
streaming (debian-multimedia has all you need, unless you build your own
mplayer)
- get mencoder-doc and read the man page - especially the last few lines
with examples about recording from TV input (I don't know your TV norm
or your input signal, so I can't give you advice for specific options)
- use your audio card's line in for audio capturing. There's quite good
advice, how to do that in mplayers man page
- capture in raw or lossless mjpeg format and PCM audio to be able to
encode as H264 or ogg/ogm later for web streaming (HTML5/Flowplayer)
without recompression artefacts
Unfortunately I don't have one of my well-probed scripts at hand right
now, but basically I did some experimenting with input size and cropping
of the captured video to find a format that suited best (beware of
interleaved input signals), captured to MJPEG/PCM and recoded to H264
for web streaming with flowplayer.
There might be some hassle finding the right settings for your audio
hardware to record from line-in. I found alsamixer to be the best tool here,
just my 2 cents,
Tom
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