Add detection for repeated audio in capturing.

content/renderer/media/media_stream_audio_processor.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/media_stream_audio_processor.h"
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/trace_event/trace_event.h"
@@ skipping 278 matching lines @@
   DCHECK(processed_data);
   DCHECK(capture_delay);
   DCHECK(new_volume);
 
   TRACE_EVENT0("audio", "MediaStreamAudioProcessor::ProcessAndConsumeData");
 
   MediaStreamAudioBus* process_bus;
   if (!capture_fifo_->Consume(&process_bus, capture_delay))
     return false;
 
+  // Detect bit-exact repetition of audio present in the captured audio.
+  // We detect only one channel.
+  audio_repetition_detector_.Detect(process_bus->bus()->channel(0),
+                                    process_bus->bus()->frames(),
+                                    1,  // number of channels
+                                    input_format_.sample_rate());
+
   // Use the process bus directly if audio processing is disabled.
   MediaStreamAudioBus* output_bus = process_bus;
   *new_volume = 0;
   if (audio_processing_) {
     output_bus = output_bus_.get();
     *new_volume = ProcessData(process_bus->channel_ptrs(),
                               process_bus->bus()->frames(), *capture_delay,
                               volume, key_pressed, output_bus->channel_ptrs());
   }
 
@@ skipping 369 matching lines @@
   if (echo_information_) {
     echo_information_.get()->UpdateAecDelayStats(ap->echo_cancellation());
   }
 
   // Return 0 if the volume hasn't been changed, and otherwise the new volume.
   return (agc->stream_analog_level() == volume) ?
       0 : agc->stream_analog_level();
 }
 
 }  // namespace content