Re: [ecasound] Cutting with ecasound?

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Subject: Re: [ecasound] Cutting with ecasound?
From: Jeremy Hall ( )
Date: Thu Sep 30 1999 - 05:21:06 EEST


Kai Vehmanen said:
> 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.
In my ecasound, setpos works as integers. No matter what I type in there,
it rou ds up.

> > 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.
well that may be a bit ugly if it works. Also, if you ever start looping,
you can't turn looping off in 13R6.

> > 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?
because when I am making up files to be sent to cdrecord, they must break
on sector boundaries. I suppose if I used dd to craft the initial track,
then I could use ecasound to add additional tracks. As long as the
ecasound process won't add bits to the length, I'm fine.

> > 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).
Is this a hard one to solve, or does it naturally show up with region
support? Please expound on what region support is.

> > 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).
If the block notion is supported, then you can feed your other formats
into the block units, for example, seconds would be 176400 bytes = 1
second, while sectors would be 2352 bytes = 1 sector.

> --
> Kai Vehmanen <> -------- CS, University of Turku, Finland
> . - linux audio processing
> . - ambient-idm-rock-... mp3/ra/wav

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