Merge 264918 "Fix the output request size for AudioBufferConvert..."

media/base/audio_buffer_converter.cc

 // Copyright 2014 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 "media/base/audio_buffer_converter.h"
 
 #include <cmath>
 
 #include "base/logging.h"
 #include "media/base/audio_buffer.h"
@@ skipping 127 matching lines @@
     const scoped_refptr<AudioBuffer>& buffer) {
   Flush();
   audio_converter_.reset();
   input_params_.Reset(
       input_params_.format(),
       buffer->channel_layout(),
       buffer->channel_count(),
       0,
       buffer->sample_rate(),
       input_params_.bits_per_sample(),
-      // This is arbitrary, but small buffer sizes result in a lot of tiny
-      // ProvideInput calls, so we'll use at least the SincResampler's default
-      // request size.
-      std::max(buffer->frame_count(),
-               static_cast<int>(SincResampler::kDefaultRequestSize)));
+      // If resampling is needed and the FIFO disabled, the AudioConverter will
+      // always request SincResampler::kDefaultRequestSize frames.  Otherwise it
+      // will use the output frame size.
+      buffer->sample_rate() == output_params_.sample_rate()
+          ? output_params_.frames_per_buffer()
+          : SincResampler::kDefaultRequestSize);
 
   io_sample_rate_ratio_ = static_cast<double>(input_params_.sample_rate()) /
                           output_params_.sample_rate();
 
   // If |buffer| matches |output_params_| we don't need an AudioConverter at
   // all, and can early-out here.
   if (!IsConfigChange(output_params_, buffer))
     return;
 
+  // Note: The FIFO is disabled to avoid extraneous memcpy().
   audio_converter_.reset(
       new AudioConverter(input_params_, output_params_, true));
   audio_converter_->AddInput(this);
 }
 
 void AudioBufferConverter::ConvertIfPossible() {
   DCHECK(audio_converter_);
 
   int request_frames = 0;
 
@@ skipping 68 matching lines @@
   is_flushing_ = false;
   audio_converter_->Reset();
   DCHECK_EQ(input_frames_, 0);
   DCHECK_EQ(last_input_buffer_offset_, 0);
   DCHECK_LT(buffered_input_frames_, 1.0);
   DCHECK(queued_inputs_.empty());
   buffered_input_frames_ = 0.0;
 }
 
 }  // namespace media