[SOLVED] using JACK with KDEnlive - originally no sound from external audio card

[RickBrock]

hi, this is my first time using Kdenlive - so it may well be a rookie error.

i have pulled in an AVI clip which, when i play it, i see pictures moving but hear no sound. i can see a WAV representation under the video.
the clip plays sound and video in the Movie Player

also, i have loaded up a WAV file at 44.1 and also have no sound.

the kdenlive audio driver is set to automatic, i have Jack running so i can use an external USB sound card....but...

if i turn jack off i can get sound from my internal card (which i don't want to use)

EDITED POST - I HAVE THE ANSWER....
The Answer is.....

KDENlive does not work with JACK. However, running ALSA LOOP (ALOOP DEAMON) has provided a method by which the sound can be passed through to JACK and therefor obey all the setting QJackCTL is implementing.

Rick

[trulan]

Does Kdenlive work with Jack?  I don't remember...You can open up either Patchage or the connections tab in QJackCTL and see if any ports show up for Kdenlive when you try to play the video.

Or, since you're using Jack anyway, you could try the new Alsa Loopback daemon that comes with AVLinux 6 (this is exactly the kind of thing the loopback daemon is meant for, BTW).  With Jack running, start Alsa Loopback (it's in the audio menu), then start Kdenlive and see what happens.  If you still have no sound, set Kdenlive to use alsa, and the loopback soundcard.

[davephillips]

Does Kdenlive work with Jack?

IIRC Kdenlive doesn't handle its audio at all, MLT does. Apparently JACK support is built into MLT but I don't think it's available to Kdenlive. At any rate, I run Kdenlive on three different systems, none of which permit its use with JACK. The Loopback should work though, and I'd like to hear from anyone who has it working with Kdenlive, it'd get rid of another irritiation I have with that program.

Best,

dp

[RickBrock]

Many thanks, Aloop Deamon got it!

There is no KDEnlive in 'Patchage' but running aloop deamon just 'made it work'

Rick

[davephillips]

Many thanks, Aloop Deamon got it!

Hey Rick, glad to hear you got it working. Can you post how you did it ? Did you just run 'alsaloop -d' or did you add other options ?

Best,

dp

[GMaq]

Hi,

Essentially Kdenlive needs an available ALSA device as always so if you use the same default audio device for ALSA and JACK if you are working with Kdenlive on it's own then it is simplest just to run Kdenlive without JACK running on the system at all and let it use the ALSA device. If you want it use Kdenlive with JACK the aloop daemon is easiest to run by selecting it's launcher from the Audio menu that way it will launch with it's xterm to tell you what's it's up to.

Note that MLT only has JACK transport support not audio support and to enable JACK transport you have to run melt with a '-jack' switch. I don't know of anybody who uses it this way and I haven't seen much at all about it on the Kdenlive forums.

See page 39 of the AV Linux User Manual for more info: http://bandshed.net/pdf/AV6Manual.pdf

[trulan]

Hi Dave,

The idea with the loopback daemon was to have it be a click-and-go, 'just works' setup.

Here's how it works:  Clicking on the menu entry for the alsa-loopback daemon runs this:

Code:

xterm -hold -e "/usr/bin/aloop-daemon"

..though if you want to launch it from a terminal, 'aloop-daemon' would work as well.

aloop-daemon is a cool little python script (created by falktx) that makes sure Jack is running, then creates Jack input and output ports with alsa-in and alsa-out (or zita-a2j and zita-j2a, with a little script modification), and connects them to system record and system playback.  The Jack clients are persistent, so you can connect them wherever you want and they will not be dropped unless Jack or aloop-daemon shuts down.

The only 'sticky' part about the whole deal is that this loopback setup requires a special .asoundrc file, which, if left in your home folder, plays all your audio into the loopback soundcard, meaning you have no sound unless Jack and aloop-daemon are running.  So we (mostly Fragadelic, with a little input from me) made the script copy the loopback .asoundrc into place at startup of the daemon, and remove it when it shuts down.  This should work for everyone except those who are already using .asoundrc, such as users with multiple soundcards or certain USB soundcards.  In that case, the script will back up the existing .asoundrc and restore it when it shuts down.  The script isn't overly intelligent with this and could potentially mess up the handling of the .asoundrc's, so caution (and a good backup) is recommended if you're using an .asoundrc.  It could also potentially leave the aloop .asoundrc behind, say if you have a kernel panic, leaving you with no sound without Jack until .asoundrc is deleted.

But the idea was to have something that was as simple as possible to use, and from what Rick says, it seems to have been successful.

[RickBrock]

hi dp,

as the Heros have stated....

I start Jack in 44.1 (for some reason 48K didn't work)

I click on FalkTX's icon for Aloop Deamon in the Audio menu

I open KDEnlive

I am happy...

I hope you can make it work too. but now all i have to learn to do is edit.... (I'm very used to FCP and lots of people say that KDEnlive is like FCP.... but it isn't. it however rather jolly good.

Happy editing,

Rick

[kalimerox]

@trulan

the loopback daemon is just fantastic!! it s the first time i can use kdenlive w/ jack and everything else just running through jack, this was the missing link in linux and sound, thank you so much for this!!