ppapi/shared_impl/ppb_audio_config_shared.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ppapi/shared_impl/ppb_audio_config_shared.h"
   6 #include "ppapi/thunk/enter.h"
   7 #include "ppapi/thunk/ppb_instance_api.h"
   8
   9 namespace ppapi {
  10
  11 PPB_AudioConfig_Shared::PPB_AudioConfig_Shared(ResourceObjectType type,
  12                                                PP_Instance instance)
  13     : Resource(type, instance),
  14       sample_rate_(PP_AUDIOSAMPLERATE_NONE),
  15       sample_frame_count_(0) {
  16 }
  17
  18 PPB_AudioConfig_Shared::~PPB_AudioConfig_Shared() {
  19 }
  20
  21 PP_Resource PPB_AudioConfig_Shared::Create(
  22     ResourceObjectType type,
  23     PP_Instance instance,
  24     PP_AudioSampleRate sample_rate,
  25     uint32_t sample_frame_count) {
  26   scoped_refptr<PPB_AudioConfig_Shared> object(
  27       new PPB_AudioConfig_Shared(type, instance));
  28   if (!object->Init(sample_rate, sample_frame_count))
  29     return 0;
  30   return object->GetReference();
  31 }
  32
  33 // static
  34 uint32_t PPB_AudioConfig_Shared::RecommendSampleFrameCount_1_0(
  35     PP_AudioSampleRate sample_rate,
  36     uint32_t requested_sample_frame_count) {
  37   // Version 1.0: Don't actually query to get a value from the
  38   // hardware; instead return the input for in-range values.
  39   if (requested_sample_frame_count < PP_AUDIOMINSAMPLEFRAMECOUNT)
  40     return PP_AUDIOMINSAMPLEFRAMECOUNT;
  41   if (requested_sample_frame_count > PP_AUDIOMAXSAMPLEFRAMECOUNT)
  42     return PP_AUDIOMAXSAMPLEFRAMECOUNT;
  43   return requested_sample_frame_count;
  44 }
  45
  46 // static
  47 uint32_t PPB_AudioConfig_Shared::RecommendSampleFrameCount_1_1(
  48     PP_Instance instance,
  49     PP_AudioSampleRate sample_rate,
  50     uint32_t sample_frame_count) {
  51   // Version 1.1: Query the back-end hardware for sample rate and buffer size,
  52   // and recommend a best fit based on request.
  53   thunk::EnterInstanceNoLock enter(instance);
  54   if (enter.failed())
  55     return 0;
  56
  57   // Get the hardware config.
  58   PP_AudioSampleRate hardware_sample_rate = static_cast<PP_AudioSampleRate>(
  59       enter.functions()->GetAudioHardwareOutputSampleRate(instance));
  60   uint32_t hardware_sample_frame_count =
  61       enter.functions()->GetAudioHardwareOutputBufferSize(instance);
  62   if (sample_frame_count < PP_AUDIOMINSAMPLEFRAMECOUNT)
  63     sample_frame_count = PP_AUDIOMINSAMPLEFRAMECOUNT;
  64
  65   // If client is using same sample rate as audio hardware, then recommend a
  66   // multiple of the audio hardware's sample frame count.
  67   if (hardware_sample_rate == sample_rate && hardware_sample_frame_count > 0) {
  68     // Round up input sample_frame_count to nearest multiple.
  69     uint32_t multiple = (sample_frame_count + hardware_sample_frame_count - 1) /
  70         hardware_sample_frame_count;
  71     uint32_t recommendation = hardware_sample_frame_count * multiple;
  72     if (recommendation > PP_AUDIOMAXSAMPLEFRAMECOUNT)
  73       recommendation = PP_AUDIOMAXSAMPLEFRAMECOUNT;
  74     return recommendation;
  75   }
  76
  77   // Otherwise, recommend a conservative 50ms buffer based on sample rate.
  78   const uint32_t kDefault50msAt44100kHz = 2205;
  79   const uint32_t kDefault50msAt48000kHz = 2400;
  80   switch (sample_rate) {
  81     case PP_AUDIOSAMPLERATE_44100:
  82       return kDefault50msAt44100kHz;
  83     case PP_AUDIOSAMPLERATE_48000:
  84       return kDefault50msAt48000kHz;
  85     case PP_AUDIOSAMPLERATE_NONE:
  86       return 0;
  87   }
  88   // Unable to make a recommendation.
  89   return 0;
  90 }
  91
  92 // static
  93 PP_AudioSampleRate PPB_AudioConfig_Shared::RecommendSampleRate(
  94     PP_Instance instance) {
  95   thunk::EnterInstanceNoLock enter(instance);
  96   if (enter.failed())
  97     return PP_AUDIOSAMPLERATE_NONE;
  98   PP_AudioSampleRate hardware_sample_rate = static_cast<PP_AudioSampleRate>(
  99     enter.functions()->GetAudioHardwareOutputSampleRate(instance));
 100   return hardware_sample_rate;
 101 }
 102
 103 thunk::PPB_AudioConfig_API* PPB_AudioConfig_Shared::AsPPB_AudioConfig_API() {
 104   return this;
 105 }
 106
 107 PP_AudioSampleRate PPB_AudioConfig_Shared::GetSampleRate() {
 108   return sample_rate_;
 109 }
 110
 111 uint32_t PPB_AudioConfig_Shared::GetSampleFrameCount() {
 112   return sample_frame_count_;
 113 }
 114
 115 bool PPB_AudioConfig_Shared::Init(PP_AudioSampleRate sample_rate,
 116                                   uint32_t sample_frame_count) {
 117   // TODO(brettw): Currently we don't actually check what the hardware
 118   // supports, so just allow sample rates of the "guaranteed working" ones.
 119   if (sample_rate != PP_AUDIOSAMPLERATE_44100 &&
 120       sample_rate != PP_AUDIOSAMPLERATE_48000)
 121     return false;
 122
 123   // TODO(brettw): Currently we don't actually query to get a value from the
 124   // hardware, so just validate the range.
 125   if (sample_frame_count > PP_AUDIOMAXSAMPLEFRAMECOUNT ||
 126       sample_frame_count < PP_AUDIOMINSAMPLEFRAMECOUNT)
 127     return false;
 128
 129   sample_rate_ = sample_rate;
 130   sample_frame_count_ = sample_frame_count;
 131   return true;
 132 }
 133
 134 }  // namespace ppapi