Re: [ecasound] Cutting with ecasound?

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Subject: Re: [ecasound] Cutting with ecasound?
From: Kai Vehmanen (kaiv@wakkanet.fi)
Date: Wed Sep 29 1999 - 22:07:13 EEST

On Wed, 29 Sep 1999, Jeremy Hall wrote:

> We need a better way of doing this than seconds=integers

Seconds are always floating-point values in ecasound...
(for instance "setpos 1.5000029" works). Not very
user-friendly but you get the precision.

> My thoughts were that you could do:
> set units=hours:minutes:seconds:sectors

Hmm, I've thought about this. Another way to do it would
be to use SMPTE format (Hours: Mins: Secs: Frames). Still,
I'd like to use something more precise and
context free. Sectors don't really relate to audio information
and SMPTE frame can mean different things (24FPS, 25FPS,
30FPS-drop, 30FPS-nondrop)... Internally ecasound uses
samples, but this again is dependent on sample rate. I've
found floating-point representation of seconds to be a good
compromise.

> same as typing set pos=2:0 (remember that there are 75 sectors (2352
> bytes) in a second)

Hmm, why do you want to use sectors?

> A mode should be invented so that merging audio does not result in a snap
> where the two wave forms meet. I can get better precision with dd now
> than ecasound, and I'd like to fix that--I don't really like having to
> write down sector offsets into a file to clip out some data.

Well, as ecasound doesn't currently supporting cutting, this isn't
a problem, but I admit that this has to be addressed in the future
(1.6.x versions will have region-support).

> set units=hours,minutes,seconds,sectors,samples
[...]
> units could be hours, minutes, seconds, sectors, blocks, or samples.

This might work. By default command line options and interactive mode
would use seconds (f-point), but this could be reconfigured. I guess
hard-coded commands would do (timeformat_smpte30, timeformat_seconds,
timeformat_mseconds, etc). 

--
Kai Vehmanen <kaiv@wakkanet.fi> -------- CS, University of Turku, Finland
 . http://www.wakkanet.fi/ecasound/ - linux audio processing
 . http://www.wakkanet.fi/sculpscape/ - ambient-idm-rock-... mp3/ra/wav

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