<wavetrack name="Narration" channel="2" linked="0" mute="0" solo="0" height="154" minimized="0" rate="44100" gain="1" pan="0">
<waveclip offset="18.55777090">
<sequence maxsamples="524288" sampleformat="131073" numsamples="780681">
<waveblock start="0">
<simpleblockfile filename="e00008d7.au" len="337046" min="-0.778839" max="0.725403" rms="0.090997"/>
</waveblock>
<waveblock start="337046">
<simpleblockfile filename="e0000c1a.au" len="443635" min="-0.711731" max="0.792633" rms="0.114152"/>
</waveblock>
</sequence>
<envelope numpoints="1">
<controlpoint t="17.702494331066" val="1.000000000000"/>
</envelope>
</waveclip>
Disclaimer: this is only what I can infer from the above snippet - I haven’t been able to find a specification of the Audacity XML format.
Wavetrack: a track in Audacity
In this case, the track is named “Narration”, [don’t know what ‘channel=“0”’ and ‘linked=“0”’ mean], it is not muted or soloed, its height on the screen is 154 pixels, it is not minimized, its sample rate is 44100 samples per second, its gain is set to 1, and its pan is set to 0 (panned to the middle).
Waveclip: a clip within a track. A track may contain many clips, but will always contain at least one.
In this case this waveclip is offset 18.55777090 seconds from the start of the track
Sequence: begins a series of waveblocks (?)
Maxsamples is (?) the maximum number of samples a waveblock (?) can contain. Don’t know what the ‘sampleformat’ codes are, but this one means 16-bit integer PCM. Numsamples is the number of samples in the sequence.
Waveblock: a block of audio - seems to usually (or always?) contain one simpleblockfile or aliasblockfile
Start is the start time (in samples) from the start of the sequence.
Simpleblockfile: finally we’re down to specifying the .au files contained in the track
Filename is simply the filename of the simpleblockfile. Note that the path is incomplete. If this Narration.aup file was in a folder named “NarrationFolder” then the complete path for this file (remember, this is an example!) is “NarrationFolder/Narration_data/e00/d00/e00008d7.au”. Also note that these .au files (as per my understanding) have a header containing data for drawing the waveform on the screen.
Len is the length of the audio in samples. The length of one sample is the inverse of the sample rate of the wavetrack.
Min is the minimum peak value of the audio in the file, max is the maximum peak value of the audio in the file. rms is indeed the root-mean-square value of the audio in the file, probably the maximum.
Envelope: if the track has an active volume envelope the control points for the envelope will be specified here.
And that’s what I can surmise. Perhaps someone who really knows can correct or confirm my assumptions.
Good luck with your project.
– Bill