After bug 918861, an AudioContext can have a sample rate different than 48000Hz. Opus only accepts input sample rate of 48000Hz, or that divide 48000 evenly. Because having a sample rate of 44100Hz on the AudioContext will be pretty common, we need to support resampling the input properly.

Comment on attachment 815374 [details] [diff] [review] When an AudioContext is not running at 48kHz, resample the input of the MediaRecorder when encoding in Opus. r= Review of attachment 815374 [details] [diff] [review]: ----------------------------------------------------------------- ::: content/media/encoder/OpusTrackEncoder.cpp @@ +147,5 @@ > > // The granule position is required to be incremented at a rate of 48KHz, and > // it is simply calculated as |granulepos = samples * (48000/source_rate)|, > // that is, the source sampling rate must divide 48000 evenly. > + // If this constraint is not satified, we resample the input to 48kHz. "satisfied" ::: content/media/encoder/OpusTrackEncoder.h @@ +7,5 @@ > #define OpusTrackEncoder_h_ > > +#define OUTSIDE_SPEEX > +#define RANDOM_PREFIX speex > +#include "speex/speex_resampler.h" I think we should create a SpeexResampler.h #include file which defines these, and #include it everywhere in Gecko that uses Speex. We might even want to wrap it in a C++ class that automatically calls speex_resampler_destroy. Although, I don't even know why you're #defining OUTSIDE_SPEEX here when we don't do that anywhere else that uses Speex resampling. @@ +38,5 @@ > DATA > } mEncoderState; > > /** > + * Get the samplerate of the data to be fed to the opus encoder. This might be Opus

https://hg.mozilla.org/integration/mozilla-inbound/rev/6ca71aca6e9e, pushed with comments addressed.