I have given a bit of thought to the audio-fade...
I appologize if I will be repeating things already said
or writting things not really interesting or relevant but...
When I edit audio in Cinelerra I very seldom edit it directly
in the curve. That is because it can be set very nicely using the
slider in the left side of the screen.
However the slider only goes down to -40dB.
But since -40dB is the lowest value and since (at the moment)
audio is automatcally cut at this point, that's OK with me.
I also don't mind about small glitch which may occur when curve reaches
-40. For my audio/video needs this is irrelevant.
But if we speak in terms of professionality, then Cinelerra should
definitely be able do fade audio down to 0. So how to realize it.
One option would be to leave GUI as it is and just enable the editing
of curve down to -96dB (including possible patch which will make sure
that old projects won't behave funny).
But in this case the people won't be able to fade sound down to 0
just using the slider. Whenever they will want to fade it lower, they
will need to drag the point in the curve and that may be a bit
unconvenient.
On the other hand, if slider's range would be change (-96dB -> +6dB)
then it's usefulness would be (on my personal oppinion) greatly
decreased Why?
As a matter of fact, the useful range of audio fade is around -30dB
up to +6dB. (Actually I would sometimes prefer if it would go up to
+10dB or even +15dB. That is because sometimes I work with very low
volumes (speech) that must later be amplified. But that's anotehr
story...)
In addition to this one must be aware that -40dB will reduce the volume
100 times. If the highest sound would have the value of 32000, then
-40dB would reduce it to the value of 320.
In simple words this means that whenever one would go bellow -40dB,
he/she would cease editing 16bit sound and move to editing 8 but sound
instead. -60dB would mean that one is working with 5 bit sound.
To put it in even simpler words...
Fades bellow -30dB are (on my oppiniont) only useful for background
sounds and fades bellow -40dB are only useful for fade-out and fade-in.
Serious sound editing bellow this values is not possible (unless one
uses 24bit sound).
But if fader would occupy the whole range (-96dB -> +6dB), then only
1/4 or perhaps 1/3 of this range will be useful.
So what to do?
What I propose is to make a volume slider with sqare or broken
characteristc:
Perhaps something like this...
if ( fade_value <= 0.85*max_fade_value )
value = DB::fromdb(fade_value);
else
value = k2 * DB::fromdb(fade_value);
Where max_fade_value is the maximum range of the fader
and k is the konstant which will bring slider down to
-96dB when it reaches it's maximum range.
In this way the slider's range will stay the same up to
85% of the range. But when we will want to silence the track
completely, it will plunge down to -96 (when slider reachs it's full
range).
So this is the idea. It is just an idea though
but I hope it may be useful consideration.
Miha
P.S. Sorry for writting such a long letter.
But sometimes typing relaxes me ;)
On pet, 2006-10-06 at 03:39 -0300, rafael2k wrote:
> i agree.
> lets choose a way to do and use that way.
>
>
> bye,
> rafael diniz
>
> Em Quinta 05 Outubro 2006 22:16, Pierre Dumuid escreveu:
> > Rafael2k,
> >
> > I could "quickly submit a commit" that makes the default range -40 dB,
> > but I was gonna wait until the backward compatibility patch was
> > implemented. (the patch consists of looking for a project-setting for
> > the NEGINFINTYGAIN, and if it wasn't set, set it to -40 dB, whilst all
> > new projects should have a default of -96 dB being the maximum
> > attenuation possible for 16 bit audio)
> >
> > Looking at the svn history, I was a bit weary that there are so many
> > patches for this auto-curves stuff, so I wanted to limit the commits for
> > this topic.
> >
> > Pierre
> >
> > rafael2k wrote:
> > > thanx all,
> > > now, with the right range, its ok.
> > > btw, the default range of audio can be changed to 'what work' :-)
> > >
> > > after the r836, i'm uploading the new cinelerra version to
> > > i'm uploading the cinelerra packages for slackware 11.0 to:
> > > http://slack.sarava.org/packages/slackware/slackware-11.0/multimedia/
> > > i'll write a readme for instalation.
> > >
> > > to compile yourself, use the slackbuilds:
> > > http://slack.sarava.org/slackbuilds/
> > >
> > > bye,
> > > rafael diniz
> > >
> > > Em Quinta 05 Outubro 2006 20:13, Pierre Marc Dumuid escreveu:
> > >> At the moment, the default range I set for the audio faders -80 to 6
> > >> dB. A few days later I discovered that internally anything less than
> > >> -40 dB cinelerra forces to -Inf dB, hence I created a patch that makes
> > >> anything less than 40 dB to be clipped at 40 dB to indicate to the user
> > >> that this is a low the sound needs to go. ( The -40 dB was to be
> > >> changed to -96 dB at some point later with a backward compatibilty
> > >> patch.)
> > >>
> > >> Anyhow, this is the reason that the fade curve doesn't go below -40 dB
> > >> (being halfway down the track). Please change the -80 dB in the audio
> > >> range to -40 dB if that helps. You will notice you can place a keyframe
> > >> below -40 dB, and this is valid, it causes the auto curve to have a
> > >> steeper shape than if the keyframe sat at -40 dB.
> > >>
> > >> Pierre
> > >>
> > >> rafael2k wrote:
> > >>> hi all,
> > >>> i'm facing a bug in the audio fade line in my fresh slack 11 w/ the
> > >>> r909.
> > >>>
> > >>> the range is correct, the keyframes can be placed ok, but the white
> > >>> line do not go down the center of the track.
> > >>>
> > >>> anyone noticed that?
> > >>>
> > >>> bye,
> > >>> rafael diniz
>
_______________________________________________
Cinelerra mailing list
[email protected]
https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
