Re: [ecasound] ECI question

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Subject: Re: [ecasound] ECI question
From: Kai Vehmanen (
Date: Sat Feb 17 2001 - 14:33:38 EET

On Tue, 13 Feb 2001, Luke Tindall wrote:

> A gui client linked to libecasound & ECI (in this case the C version) needs
> to create a wave plot for each of the files loaded into the current chain.
> Currently the client will need to open each file and load the data into
> memory before producing the plot. As the data is already loaded by ecasound,
> can it be accessed through the ECI interface? I'm thinking (well trying at

Actually the data is not loaded by ecasound. As ecasound is designed to
handle _large_ audio files, loading whole audio files to memory is only
done when specifically requested for (ie. the mmap toggle with .wav and
.raw files).

So to do a wave-plot, you need to separately access the audio files. Of
course, you could use ecasound i/o classes and routines for the low-level
work, but this cannot be done through the ECI API (sample-level access
not provided). But it's not a problem to use external routines, while
ecasound/ECI handles the disk-to-audio streaming.

A good example of this is ecawave. Its audio playback and wave-plot parts
are completely separate. Ecawave just passes the current-position info
from the ecasound instance to the plot widget and vice versa.

As for doing the wave-plot itself, there're few good libraries/code
available. For instance Ardour uses a customized version of David
Bartold's gtkwaveview.

 . ... [ audio software for linux ] /\ . 
 . [ my armchair-tunes mp3/ra/wav ]

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