Re: [Denemo-devel] Audio Mixer

[Richard Shann]

On Wed, 2012-03-28 at 10:16 -0500, Jeremiah Benham wrote:
> On 03/13/2012 05:05 AM, Richard Shann wrote:
> > 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.
> I am confused here. I am getting this error when loading a .wav file:
> sndfile: No Error. sample rate is 44100 channels 2 containing 16539263
That is just debug chatter - it is saying there is no error in the
loading of the file. This file should be fine as it has the right sample
rate 44100 and the right number of channels. There are 16539263 samples
in it, which should be 16539263/44100 seconds IIRC. There is actually
nothing done if the sample rate were wrong, I am not sure what would
result. But what you have is fine. I think something bad happens if you
load a non-audio file by mistake (restart denemo). I have only
tested .ogg files so far.
> 
> How is the sampling rate that denemo expects set?
The audio mixer here is hard-coded to expect 44100, it could be set to
expect Denemo.prefs->sample_rate or whatever it is called.
Once you have the "No Error" message you should be able to use
Playback->Audio->Synchronize Audio which will play the audio (lh
channel) and take keypresses from you (space bar) to time the measures
by.

Richard

>  Or.. What is the rate 
> that it expects?
> 
> Jeremiah
> 
> >   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
> >
> >
> >
> > _______________________________________________
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> > https://lists.gnu.org/mailman/listinfo/denemo-devel
> 
> 
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