Make OS audio buffer size limits visible.

media/audio/pulse/audio_manager_pulse.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/pulse/audio_manager_pulse.h"
 
 #include "base/command_line.h"
 #include "base/environment.h"
 #include "base/logging.h"
 #include "base/nix/xdg_util.h"
 #include "base/stl_util.h"
 #if defined(USE_ALSA)
 #include "media/audio/alsa/audio_manager_alsa.h"
 #endif
 #include "media/audio/audio_device_description.h"
 #include "media/audio/pulse/pulse_input.h"
 #include "media/audio/pulse/pulse_output.h"
 #include "media/audio/pulse/pulse_util.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/channel_layout.h"
+#include "media/base/limits.h"
 
 namespace media {
 
 using pulse::AutoPulseLock;
 using pulse::WaitForOperationCompletion;
 
 // Maximum number of output streams that can be open simultaneously.
 static const int kMaxOutputStreams = 50;
 
-// Define bounds for the output buffer size.
-static const int kMinimumOutputBufferSize = 512;
-static const int kMaximumOutputBufferSize = 8192;
-
 // Default input buffer size.
 static const int kDefaultInputBufferSize = 1024;
 
 AudioManagerPulse::AudioManagerPulse(std::unique_ptr<AudioThread> audio_thread,
                                      AudioLogFactory* audio_log_factory,
                                      pa_threaded_mainloop* pa_mainloop,
                                      pa_context* pa_context)
     : AudioManagerBase(std::move(audio_thread), audio_log_factory),
       input_mainloop_(pa_mainloop),
       input_context_(pa_context),
@@ skipping 113 matching lines @@
   DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
   return MakeInputStream(params, device_id);
 }
 
 AudioParameters AudioManagerPulse::GetPreferredOutputStreamParameters(
     const std::string& output_device_id,
     const AudioParameters& input_params) {
   // TODO(tommi): Support |output_device_id|.
   VLOG_IF(0, !output_device_id.empty()) << "Not implemented!";
 
-  int buffer_size = kMinimumOutputBufferSize;
+  int buffer_size = limits::kMinAudioBufferSize;
   int bits_per_sample = 16;
 
   // Query native parameters where applicable; Pulse does not require these to
   // be respected though, so prefer the input parameters for channel count.
   UpdateNativeAudioHardwareInfo();
   int sample_rate = native_input_sample_rate_;
   ChannelLayout channel_layout = GuessChannelLayout(native_channel_count_);
 
   if (input_params.IsValid()) {
     bits_per_sample = input_params.bits_per_sample();
     channel_layout = input_params.channel_layout();
     buffer_size =
-        std::min(kMaximumOutputBufferSize,
+        std::min(static_cast<int>(limits::kMaxAudioBufferSize),
                  std::max(buffer_size, input_params.frames_per_buffer()));
   }
 
   int user_buffer_size = GetUserBufferSize();
   if (user_buffer_size)
     buffer_size = user_buffer_size;
 
   return AudioParameters(AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout,
                          sample_rate, bits_per_sample, buffer_size);
 }
@@ skipping 57 matching lines @@
                                                   const pa_server_info* info,
                                                   void* user_data) {
   AudioManagerPulse* manager = reinterpret_cast<AudioManagerPulse*>(user_data);
 
   manager->native_input_sample_rate_ = info->sample_spec.rate;
   manager->native_channel_count_ = info->sample_spec.channels;
   pa_threaded_mainloop_signal(manager->input_mainloop_, 0);
 }
 
 }  // namespace media