[pulseaudio-discuss] [PATCH v3 22/24] echo-cancel: Use webrtc's deinterleaved API

[Arun Raghavan]

On Wed, 2016-02-17 at 18:36 +0530, Arun Raghavan wrote:
> On Tue, 2016-02-16 at 14:20 +0200, Tanu Kaskinen wrote:
> > On Mon, 2016-01-18 at 13:06 +0530, arun at accosted.net wrote:
> > > This is required to have unequal channel counts on capture in and
> > > out
> > > streams, which is needed for beamforming to work.
> > 
> > The commit message should mention why the sample format was changed
> > to
> > float.
> 
> Okay.
> 
> > >  void pa_webrtc_ec_play(pa_echo_canceller *ec, const uint8_t
> > > *play) {
> > >      webrtc::AudioProcessing *apm = (webrtc::AudioProcessing*)ec-
> > > >params.webrtc.apm;
> > > -    webrtc::AudioFrame play_frame;
> > >      const pa_sample_spec *ss = &ec->params.webrtc.play_ss;
> > > +    int n = ec->params.webrtc.blocksize;
> > > +    float **buf = ec->params.webrtc.play_buffer;
> > > +    webrtc::StreamConfig config(ss->rate, ss->channels, false);
> > >  
> > > -    play_frame.num_channels_ = ss->channels;
> > > -    play_frame.sample_rate_hz_ = ss->rate;
> > > -    play_frame.interleaved_ = true;
> > > -    play_frame.samples_per_channel_ = ec-
> > > >params.webrtc.blocksize;
> > > -
> > > -    pa_assert(play_frame.samples_per_channel_ <=
> > > webrtc::AudioFrame::kMaxDataSizeSamples);
> > > -    memcpy(play_frame.data_, play, ec->params.webrtc.blocksize *
> > > pa_frame_size(ss));
> > > +    pa_deinterleave(play, (void **) buf, ss->channels,
> > > pa_sample_size(ss), n);
> > >  
> > > -    if (apm->ProcessReverseStream(&play_frame) !=
> > > webrtc::AudioProcessing::kNoError)
> > > +    if (apm->ProcessReverseStream(buf, config, config, buf) !=
> > > webrtc::AudioProcessing::kNoError)
> > >          pa_log("Failed to process playback stream");
> > > +
> > > +    /* FIXME: we need to be able to modify playback samples */
> > 
> > This comment should say also why we need to be able to modify them
> > (and
> > I also don't understand what's preventing us from doing so now).
> 
> Reworded this as:
> 
> /* FIXME: we need to be able to modify playback samples, which we
> can't
>  * currently do. This is because module-echo-cancel processes
> playback
>  * frames in the source thread, and just stores playback chunks as
> they
>  * pass through the sink. */
> 
> > > @@ -573,4 +575,9 @@ void pa_webrtc_ec_done(pa_echo_canceller *ec)
> > > {
> > >          delete (webrtc::AudioProcessing*)ec->params.webrtc.apm;
> > >          ec->params.webrtc.apm = NULL;
> > >      }
> > > +
> > > +    for (i = 0; i < ec->params.webrtc.rec_ss.channels; i++)
> > > +        pa_xfree(ec->params.webrtc.rec_buffer[i]);
> > > +    for (i = 0; i < ec->params.webrtc.play_ss.channels; i++)
> > > +        pa_xfree(ec->params.webrtc.play_buffer[i]);
> > 
> > I think it's not guaranteed that rec_ss and play_ss are initialized
> > at
> > this point. You should check that rec_buffer and play_buffer are
> > non-
> > NULL before accessing them.
> 
> There should not be a path where rec_buffer and play_buffer are not
> initialised before done, but I'll add that check in case this becomes
> possible in the future.

Shouldn't be necessary, actually. pa_xfree() is NULL-safe.

-- Arun