Re: Space and widget suitability problem

[Paul Davis <pbd op net>]

>> Do you plan to display audio waveforms?  I'm working on a timeline
>> editor for video editing software and would like to display the
>> waveforms for the audio tracks.  I'm hoping something out there already
>> exists so I don't have to recreate the wheel.

google for libgtkwaveform by david barthold. its pretty good. 

notice however, and this extremely important: i have been involved in
several attempts at displaying waveforms, and the way its done at
*every* level depends hugely on the context. i stopped using david's
work because it didn't work for the editing model my DAW
(ardour.sf.net) in which "regions" of audio are moved around. i
switched to the Canvas and wrote my own canvas-waveview widget, which
is loosely based on his code. other people have written waveform
display code that works for different editing models, for example the
one where the audio is a single contiguous object. basically, you
can't have it all: there is no way to write a truly generic waveform
display widget. for some things, a canvas-like item is desirable, for
other things a widget is nice, and for either there are different ways
to draw the waveform. the existence of peakfiles makes a large
difference to the design too, and is absolutely fundamentally
necessary for pro work. i recorded a 2 hour session last night in
which the individual audio files are about 1.3GB in size. when you
zoom to see the whole session, how long do you think it will take to
just *read* the data to compute the waveform display if you have to
read the actual audio file?

you should also check out sweep and gnoise, two existing audio editors
that are both written with gtk and have waveform displays.

--p