[Denemo-devel] Audio Mixer

[Richard Shann]

There is a first draft of the audio mixer in git now.
With the File->Open->Open Source Audio command you can select a file
(must match your frame rate, and have two channels) to mix with the
usual Denemo synthesizer output. The "mixing" is done in the crudest
possible manner, taking one stereo channel from each.
When you have source audio loaded, additional widgets appear in the
playback controls to set the volume relative to the synth output, and to
set the lead-in - delay or trim before the audio starts.
Under the Playback->Audio menu are commands to perform bar-by-bar
synchronization. You press the space bar once for each bar in the audio,
and Denemo creates a timing track - a staff with a whole measure rest
and a tempo setting for each measure.
On my machine the accuracy of this synchronization is only a few
percent, but my machine is very old, please let me know how this works
on your machine. It may be that the synchronization script should listen
for every second bar or so.

The original motivation for this feature is creating a transcription
from an audio source. Once synchronized, when you press play the score
and the audio playback in synch. You can create a loop, editing and
listening while the music plays back. 

Other possibilities
      * I imagine that it would be possible to create extra written
        parts to an audio track using this feature.
      * It would be possible to output audio in the same way that we
        currently output MIDI notes (e.g. on entering a note we output
        the pitch via MIDI). So, for example, we could output
        spoken/sound-effect feedback on change of prevailing duration,
        start of triplet etc. At the moment, we are limited to GM Midi
        instruments, as used for example for the rhythm feedback.

Comments welcome!

Richard