Hi,

With the 0.7.8 release approaching, I think the non functionning audio effects should be removed. In fact, according to the list I made it seems that most problems come from the Sox audio effects. It could be an issue with the sox plugins I have on my computer, but if it isn't I would suggest deactivating all sox plugins for the time being (along with Reverb and Rate Scaler which don't seem to work).

Does anyone disagree with this ?

Cheers,
Hugh

PS : and congrats everyone for the amazing work that has gone into Kdenlive (and the website !) these last months !

2010/6/25 Hugh Tebby <hugh.tebby@gmail.com>
Hi everyone,

I've listed all the audio effects that I have, and here's what I find :

Working perfectly:
- Declipper: I suppose it works... not sure how to test
- Vinyl 
- Room reverb
- Pitch Scaler
- Pitch Shift
- Volume

Tweek needed:
- Equalizer: Not enough controls (8 ?), and vertical sliders would be better
- Gain: expecting dB instead of %, should be under "audio correction" folder
- Limiter: seems to work... but no idea what it really does (and what is the release time ?)
- Mono to stereo: left to right only, options for right to left would be good
- Mute: just gain effect with fixed gain to 0 and not modifiable (weird from a user pov)
- Normalise: gain effect with fixed gain to 0, not modifiable and normalise option activated (weird from a user pov)
- Phaser: Ok, but Rate doesn't seem to affect the sound
- Sox band: width OK, but Center Frequency doesn't work

Not usable:
- Sox strech: Window ok but too powerful, Factor does nothing. Sox recommends using the Tempo effect instead of stretch
- Sox Pitch Shift: awful sound
- Sox Bass: awful sound
- Rate Scaler: Works but ugly (repeats every second or so ), user should be able to change the 'segment' size (if possible) 

No effect:
- Sox Echo
- Sox Flanger
- Sox Gain
- Sox Phaser
- Sox Reverb
- Sox Vibro
- Reverb


Propose that all non fonctionning or unusable effects be removed before the next release (either blacklist or moving the xmls away into another folder for the time being). I'll look into the "tweak needed" effects later on to see if I can do something.

Unfortunately the LADSPA plugins website is down, so no documentation is available for those effects...


Cheers, 
Hugh


2010/6/4 Hugh Tebby <hugh.tebby@gmail.com>

Thanks for your answers Dan. I suppose I'l have to dive down the rabbit hole into MLT wonderland !

I'll be looking into this in the next few weeks. Actually I think that even the simple first step of disabling effects that don't work at the moment would be quite useful, so I'll start off with that.

2010/6/3 Dan Dennedy <dan@dennedy.org>

2010/5/31 wille <wille.yyz@gmail.com>:
> Yes, left/right stereo balance.
>
> It would be very useful a feature that allow split a stereo audio clip in
> two mono clips.

Well, now you have requested two different new features when Hugh was
volunteering to do some cleanup. The lack of balance/pan is already
well known and on my todo list. I praise Hugh's interest in
volunteering for some cleanup and would be saddened to see him
distracted.

One thing you can do today is to split the audio and video and add the
clip again on an audio track. Then, use the channelcopy filter on both
audio clips to isolate left vs. right. Finally, you can use the
keyframable volume effect on each to do panning. Unfortunately, today
channelcopy is exposed in Kdenlive as simply "Mono to stereo," but you
can alter the effect XML file for that to add "to" and "from" channel
parameters (0 is left, 1 is right). ("Mono to stereo" may seem like a
strange name, but it was added specifically for the case where a clip
only has a mono track and you do not want it both channels and not
just left.)

MLT and Kdenlive does not support the notion of a different number of
channels per track. So your second request is much longer term, if
ever, especially considering that I am still working on proper
multichannel (>2) support. I have been doing a lot with multichannel
in the past year for broadcast applications of MLT, but there are
still some gaps to add it in Kdenlive. One of these is surround
panning, which would also be capable of stereo.

> 2010/5/31 Hugh Tebby <hugh.tebby@gmail.com>
>>
>> Do you mean left/right stereo balance ? I don't think there's such an
>> effect available in Sox or Ladspa... Would probably have to be done directly
>> with MLT...

That is correct.

>> 2010/5/31 wille <wille.yyz@gmail.com>
>>>
>>> By the way, I feel the need of a Balance audio effect or a similar tool.
>>>

--
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