[Kdenlive-devel] Questions about audio effects

[Hugh Tebby]

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 at 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 at 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 at dennedy.org>
>>
>> 2010/5/31 wille <wille.yyz at 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 at 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 at gmail.com>
>>> >>>
>>> >>> By the way, I feel the need of a Balance audio effect or a similar
>>> tool.
>>> >>>
>>>
>>> --
>>> +-DRD-+
>>>
>>>
>>> ------------------------------------------------------------------------------
>>> ThinkGeek and WIRED's GeekDad team up for the Ultimate
>>> GeekDad Father's Day Giveaway. ONE MASSIVE PRIZE to the
>>> lucky parental unit.  See the prize list and enter to win:
>>> http://p.sf.net/sfu/thinkgeek-promo
>>> _______________________________________________
>>> Kdenlive-devel mailing list
>>> Kdenlive-devel at lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/kdenlive-devel
>>>
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.kde.org/pipermail/kdenlive/attachments/20100831/3e53fc0c/attachment.html>