videojack source uploaded

nelburglooze.net wrote:

>>When using two jack servers (audio and video), the
idea is to run a
>>synch client, so that the timing comes from the
soundcard.
>>
>>Gabriel.
>>
>>    
>>
>
>The timing should not come from the soundcard. There is
no way to garantee
>that the sound chips give a timing precise enough,
especially those chips
>that are included onboard.
>
>  
>
That depends on what you are doing. If you are generating
audio and 
video, then of course you want the two streams to be in
synch.

You can either adjust the audio rate to fit the video frames
(i.e. 
resample in real time), or you can adjust the video frame
rate to fit 
the audio.

Of course, to be really accurate, you would use an external
clock 
source, like pro a/v cards do. I am not sure if jack
supports this, you 
will have to ask on the jack list.

>Could temperature influence the accuracy of the timer in
your soundchip?
>
>  
>
Undoubtedly. Again it depends on your priorities - do you
want frame 
accurate video, or do you want the video to match the actual
audio 
playback speed?

Probably you should look at netjack, and see how it handles
the timing 
issues for network audio.


>Are there video players out there that uses the timing
from the soundcard?
>
>
>  
>
Sure. LiVES takes its timings from the soundcard, (unless it
is 
receiving a remote stream - in which case it tries to play
the video at 
its proper rate, and resamples the received audio).

I believe Gstreamer also takes it's timings from the
soundcard.

Gabriel.


------------------------------------------------------------
-------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the
chance to share your
opinions on IT & business topics through brief surveys -
and earn cash
http://www.techsay.com/default.
php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Jackit-devel mailing list
Jackit-devellists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/jackit-dev
el