Audio addition/mixing does not work

Hi,

I guess I found a bug, and after a quick search through the mantis nothing turned up. So I'm gonna describe it and maybe someone knows about this or can point me to something completely different :-) (or we conclude that it is a bug and I'll file a report...)

Just for my understanding:
If I stack two audio clips on top of each other, say one in track_2 and the other in track_3, the 2 streams/tracks should be added/mixed to create one output stream (so if both streams would contain exactly the same, the output would be "double" the volume of one), right? That's how this is supposed to work, or am I getting this wrong? As opposed to video clips, where mixing is controlled by the alpha channel, right? :-)

The problem:
- I make a project with 1 Video track, 3 Audio tracks, profile DV/DVD-Pal
- I import 1 video clip (mpeg2-dvd-pal inside an mpg container, without audio) ~ 87 minutes, 3.5 GB
- I import 2 audio clips (pcm-le-16bit-2ch inside wav, ) ~ 82 and 86 minutes, 900 Mb, 950 Mb
- Every thing is fine,
- So I edit audio, add some cross fades (using fade out on one track, and fade in on the other track), work some time (~90 minutes or so), what ever ...
- Now suddenly audio mixing is not working any more: Instead of mixing the clips on the two tracks it just plays the top most of the clips (the same behavior as if it were video clips)
- That affects every thing on that two tracks including the previously working fades/mixes
- I save the project
- close Kdenlive
- open the project in a new Kdenlive -> the same, still not working
- I add a new (audio) track after last audio track: track_4 (ahhhh got that wrong sry -> track was already there of course)
- Now But mixing is working between track_3 and track_4 but still and not working between track_2 and track_3

0.7.8-0ubuntu0~sunab~maverick1
0.5.10-0ubuntu0~sunab~maverick1
on Kubuntu 10.10 64bit

Has anyone encountered that behavior before? Any ideas?

Cheers
Lain

ps.: I love Kdenlive it's nearly everything I wish for when editing video/audio -> THANKS!

FWIW audio mixing does not work at all for me. It always just plays both audio tracks, even if I do cross-fade amog them.

Note, I use audio-only tracks and use a transition there.

> f both streams would contain exactly the same, the output would be "double" the volume of one), right?

Not necessarily. There is more than one way to mix. The method you describe/expect is prone to causing clipping.

> work some time (~90 minutes or so), what ever ...
> - Now suddenly audio mixing is not working any more

That part is difficult to reproduce and debug. Probably something got "out of whack" in your project due to a bug. Feel free to post a proper bug report and attach your project file.

Hi,

thanks for your reply. Sadly I ran out of time on this issue, and managed to work around it.

> That part is difficult to reproduce and debug

Yea ... -> I still have the project file (I guess), but it never happened to me again. So I would say, until it does happen again I will not file a bug report...

Cheers
Lain