audio_manager_cras: Set minimum output buffer size per board

media/audio/cras/audio_manager_cras.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 "media/audio/cras/audio_manager_cras.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/logging.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/nix/xdg_util.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/sys_info.h"
 #include "chromeos/audio/audio_device.h"
 #include "chromeos/audio/cras_audio_handler.h"
 #include "media/audio/audio_device_description.h"
 #include "media/audio/audio_features.h"
 #include "media/audio/cras/cras_input.h"
 #include "media/audio/cras/cras_unified.h"
 #include "media/base/channel_layout.h"
 #include "media/base/localized_strings.h"
 
 // cras_util.h headers pull in min/max macros...
@@ skipping 229 matching lines @@
 }
 
 AudioInputStream* AudioManagerCras::MakeLowLatencyInputStream(
     const AudioParameters& params,
     const std::string& device_id,
     const LogCallback& log_callback) {
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
   return MakeInputStream(params, device_id);
 }
 
+int AudioManagerCras::GetMinimumOutputBufferSizePerBoard() {
+  // On faster boards we can use smaller buffer size for lower latency.
+  // On slower boards we should use larger buffer size to prevent underrun.
+  std::string board = base::SysInfo::GetLsbReleaseBoard();
+  if (board == "kevin")
+    return 768;
+  else if (board == "samus")
+    return 256;
+  return kMinimumOutputBufferSize;
+}
+
 AudioParameters AudioManagerCras::GetPreferredOutputStreamParameters(
     const std::string& output_device_id,
     const AudioParameters& input_params) {
   ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
   int sample_rate = kDefaultSampleRate;
-  int buffer_size = kMinimumOutputBufferSize;
+  int buffer_size = GetMinimumOutputBufferSizePerBoard();
   int bits_per_sample = 16;
   if (input_params.IsValid()) {
     sample_rate = input_params.sample_rate();
     bits_per_sample = input_params.bits_per_sample();
     channel_layout = input_params.channel_layout();
     buffer_size =
         std::min(kMaximumOutputBufferSize,
                  std::max(buffer_size, input_params.frames_per_buffer()));
   }
 
@@ skipping 33 matching lines @@
 
 bool AudioManagerCras::IsDefault(const std::string& device_id, bool is_input) {
   AudioDeviceNames device_names;
   GetAudioDeviceNamesImpl(is_input, &device_names);
   DCHECK(!device_names.empty());
   const AudioDeviceName& device_name = device_names.front();
   return device_name.unique_id == device_id;
 }
 
 }  // namespace media