On Tue, September 14, 2010 03:23, Patrick Millius wrote:
>
> RE analog support:
>
> Am very excited about LiVES now. I can get rid of Windows forever soon!
>
> The Hauppauge pvr 150 card did not work, not for love nor money: was in
> this pc "box" before installing latest lives. Switched out with PVR 500
> from the Windows box; and video capture working fine. Might have been
> firing up the box with a "new" card that did it. Opens as a location
> </media/video0 (or video1 for RF signal input)>
>
> Q: Audio: LiVes does not currently capture audio, as we discussed a
> while back. If I port the audio to say, Audacity, is there a way to
> synch it up?
> Most of the Hauppauge cards have stereo audio input jacks. If I was a
> bit more literate I'd write the bit of code to run audio on these under
> LiVES myself and donate it to the cause. I can deal with porting audio
> to another input & program as long as I can somehow be sure the words
> and lips synch.
>
> Thanks Gabriel-
> Patrick M.
>

Hi Patrick,
good to hear you got your TV card working in Linux.

As far as I can see there are two possible solutions to this:

a) record audio from pulse or jack when the front video source is TV card
and it is in record mode.

Possible, since LiVES already has the capability to record audio and play
back video at the same time. That would work if you could get your card to
play its audio thorugh jack or pulse. You say above that the card has
stereo audio input - do you mean output ? If so one way would be to
connect your card audio output to the soundcard line in.


b) Like you say. import a wav file from audacity and have some way of
manually syncing the audio with the video track. So what I envisage here
is you could import the audio, then play the clip back use the ctrl-up,
ctrl-down, ctrl-left, ctrl-right, ctrl-enter and ctrl-backspace keys to
get the a/v in sync (of course with "Audio follows video rate/direction"
unchecked in Preferences). Then I could set a keypress to show the a/v
offset in the message window. So you would see something like:

a/v offset is -10.39 seconds at frame 2576 with fps 25.16.

So you would then know to either cut the audio at the start or insert
silence.


Of course, neither solution takes into account dropped audio packets, so
although you might be in sync at one point there is no guarantee you would
be in sync for the whole clip. Dealing with this adds another level of
complexity (i.e. some cobination of shifting *and* time stretching audio
would be needed.)


Of the above the simplest is to implement the keypress that shows the
offset. I can probably do that very quickly. Then I can look at solution
a) after that.


Cheers,
Gabriel.



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