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Zak Wood schrieb:
> Hi,
> 
> I am in what I hope is the final stages of editting a small video clip,
> with a number of video and audio tracks. Somewhere along the line
> though, I've lost the ability to lower audio volume (using the
> keyframes). The keyframe line still responds, and I can lower or raise
> it, but the track simply doesn't change volume. I am arming/disarming
> tracks as recommended, and I've switched gangfaders on and off trying to
> find some combo that works.
> 
> I have looked for answers on google and in far too many parts of the
> manual, but I'm finding nothing - part of the problem may be that I'm
> looking for the wrong thing.
> 
> Any suggestions or help on where to start would be massively appreciated.
> 
> Cheers,
> Zak
> 

Hi Zak

maybe I don't understand your problem right. But maybe it is related to
the following problem. If not, please ignore my explanations ;-)

But I recall an ongoing discussion about a somewhat related problem, which
ended with a stalled patch and no real agreement. It's related to the 96db
of dynamic range available with 16bit PCM audio.

Maybe somehow the original author (or some patch to cinelerra way back)
concluded that about -30dB is "practically silence". Thus, now cinelerra
got the nasty habit just to switch off the sound when reaching -30dB

Of course, this is plain nonsense and on professional equipment you clearly
hear a "click" on every fade, cross fade and the like. Moreover,
you often need to set athmo at a level way below -30dB

But now the problem is: based on the quasi-naive view of sound handling,
the fade level display in Cinelerra is largely adjusted to work well
with just a range of -30dB. Just extending it to the real range available
through the media (96dB or 120dB for 24bit) would cause the rarely used
low-level range to take up most of the screen real estate. And, sadly
enough cinlerra just doesn't have the necessary program infrastructure
so you could ad a "zoom feature" in any reasonable amount of time.
I'd guess this to take at least a man month of work in the current code
base, if the intention is to do it properly and not introduce other problems.

If I recall right, somewhere in CV2.1 there was a patch which at least
makes the volume curve show this actual behaviour. Moreover there were
debates how it could be changed. But there is the problem that changing
the existing behaviour will probably render most existing sessions
invalid in a subtle way. And, again, Cinelerra lacks the necessary
infrastructure to manage different session formates to retain
backwards compatibility.

Personally I was marginally involved into this problem, as I was working
at that time on my "bezier patch", which I needed to make the fade and
camera curves basically usable in a professional setup. This patch would,
as an unintended sideffect, introduce a library function which could be
used to insert automatically interpolating keyframes to simulate the
legacy behaviour on the sound fade; thus it would then be possible
to change the meaning of "silence" from -30dB to -96dB.

Well -- it came different. I needed about 2 1/2 man months of work to
get the bezier changes done (which in a reasonably organised codebase
would be about 2 weeks of work at max). Moreover the patch necessarily
got so disruptive, that it would be a major liability with regards of
merging new upstream versions. Thus, after a first round of review
(where Pierre Dumuid greately helped me to improve the patch), this
whole effort got somewhat sidelined (and I maintain a private version
for just for my own use since then)

When professional quality is required, I always do my final sound mix
in Ardour.

Cheers
Hermann V.



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