The VideoLAN Forums

I'm using ffmpeg to stream video and audio from a WebCam over a network then using a modified version of Hyper VLC (a C# wrapper around LibVLC) to get it into Unity. After a bit of work I've managed to get the video working well, but HyperVLC doesn't handle audio so I'm trying to add it myself and I can't figure out how to get the audio data out of LibVLC.

I initialise the audio similar to the video using libvlc_audio_set_format and libvlc_audio_set_callbacks, giving it OnPlayAudio(void* data, void* samples, uint count, long pts) as the play callback. But I can't figure out how to use the parameters that method gives me. "data" is always null, and I've tried marshalling "samples" into a float array, but it only gives exponentially small values and NaNs.

I need to get the audio as a float array (with all values between 0 and 1 I believe) to give to Unity. Any help would be greatly appreciated.

I believe this is documented in the LibVLC Doxygen. IIRC, <data> is your opaque data pointer, which you set in the format callback. I'm not sure floating point is implemented yet there (though VLC supports it internally).

Thanks for your response.

Is this what you mean by the LibVLC Doxygen? Or is there a different section I should be looking at?

Can you please explain or point me to somewhere that explains what an opaque data pointer actually is?

If it doesn't come in as floats, should I marshal it as bytes or ints then scale them down into the 0-1 range floats Unity needs?

Gee, the opaque data is what you make it. LibVLC does not know or care what it is.

That doesn't make sense. Either the parameter is completely useless or it is actually used in some way. If I pass in a pointer to a float[], it can't possibly be used in the same way as if I were to pass in a pointer to a single int or a string or something else entirely.

opaque is used for your usage, so you get it in the callback.