Subject: Re: [ecasound] request modification to the .ewf file format
From: Kai Vehmanen (k_AT_eca.cx)
Date: Mon Nov 26 2001 - 00:52:55 EET
On Fri, 16 Nov 2001, Jeremy Hall wrote:
> I wish to request modification to the .ewf file format such that you may,
> if desired, specify offsets in frames rather than time-in-seconds. Can
> ecasound be told to seek to a partidcular frame in a file and start
> there? I am seeing rounding problems because I wanted to go to frame
> 100038656 and I wanted it to play for 53678848 frames. The math tells me
> this is 2084.1386666667 seconds.
[...]
> When ecasound rewrote this as cs-save, it converted to 2084.139, causing
> an offset of 16 frames. I recommend ecasound use something more exact for
For exact position and length information, sample frames is the only
sensible format (or more accurately, combination of
pos_in_sframes+sample_rate).
I think it's time to redesign the ewf code (ewf-v2). The current
format is not ideal to work with and to extend. Few ideas I've had
in mind:
- support for exact position information (ie. samples or seconds,
probably a toggle setting that lets ecasound know which format
to use when saving ewf-files)
- support for multiple audio objects
- well-defined behaviour when ewf-files is used as input and
output
- ....
Any others? Ideas on how to implement the above are welcome (for instance,
how the multiple files should be specified in ewf-v2 files, how to handle
multiple ewf-versions, xml/ascii/bin, etc)? Hmm, I guess I'll make an EDI
entry for this... "(edi-20) Ewf-v2 format."
> Also I have noticed that if you use -y:n then setpos, rw, and fw, lose
> this information and you lose sync with your audio sources. If I
> converted to .ewf instead, would setpos, rw, fw, etc work correctly?
Yes.
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