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Thread: audio library callback, timers, integrating a timeline and/or musical-grid...

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    audio library callback, timers, integrating a timeline and/or musical-grid...

    Hello,
    I'm interested in developing a sample-accurate musical-grid and timeline.

    I'm generally trying to inform the timeline of the audio sample position, relative to each block/buffer of samples, not in free-running absolute time, but stuff like a play/record "head", and the general syncing of the timeline to audio samples passing, for example if there was a playlist of audio "clips" to play from given times on a timeline (musical time but this can be reduced to sample counts at this level/layer)

    Additionally, I thought that I would ask thoughts/advice on how best to integrate the passage of time streaming audio with some time data structures.
    Any additional ideas are, of course, welcome.

    Am I confusing things that don't need to be related?

    I had thought of starting by incrementing a counter with each sample number upon the audio callback, but I can't seem to find it yet. (the audio callback, or is there one defined in each audio I/O hw interface? i.e. input_i2s.cpp and it's DMA setup, which presumably arranges the audio engine state machine for starting?)

    I'm generally a bit confused as to the state-machine of audio playback and/or recording, and if there is any higher level callback I didn't see one yet, so I can only presume that it's just the DMA pulling the interrupt? or?


    I guess I'm generally fishing for high-level overview of the internals of the audio library and pulling the usual forum tricks...
    (wasting a bit of your time to save me more time, selfish me, well, it will help other people and/or posterity I suppose, that's my excuse...)

    The docs are great as far as the consuming API goes.
    Last edited by aaronpeacock; 12-10-2020 at 12:10 AM. Reason: formatting, simplifying, clarifying

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