Work on improving PpbAudioConfig:RecommendSampleFrameCount

Add version 1.1 which will query the audio back end for the best available
sample frame count. Also add RecommendSampleRate.  Switch pepper plugin
delegate to use AUDIO_PCM_LOW_LATENCY if client request is compatible.

TEST=included
BUG=http://code.google.com/p/chromium/issues/detail?id=107572
Review URL: https://chromiumcodereview.appspot.com/9129007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@122653 0039d316-1c4b-4281-b951-d872f2087c98

26 files changed, 561 insertions, 75 deletions

diff --git a/ppapi/api/ppb_audio_config.idl b/ppapi/api/ppb_audio_config.idl
index 4c2e3a2..8ba2a28 100644
--- a/ppapi/api/ppb_audio_config.idl
+++ b/ppapi/api/ppb_audio_config.idl
@@ -9,7 +9,8 @@
  */
 
 label Chrome {
-  M14 = 1.0
+  M14 = 1.0,
+  M18 = 1.1
 };
 
 /**
@@ -51,9 +52,11 @@ enum PP_AudioSampleRate {
 interface PPB_AudioConfig {
   /**
    * CreateStereo16bit() creates a 16 bit audio configuration resource. The
-   * <code>sample_frame_count</code> should be the result of calling
-   * <code>RecommendSampleFrameCount</code>. If the sample frame count or bit
-   * rate isn't supported, this function will fail and return a null resource.
+   * <code>sample_rate</code> should be the result of calling
+   * <code>RecommendSampleRate</code> and <code>sample_frame_count</code> should
+   * be the result of calling <code>RecommendSampleFrameCount</code>. If the
+   * sample frame count or bit rate isn't supported, this function will fail and
+   * return a null resource.
    *
    * A single sample frame on a stereo device means one value for the left
    * channel and one value for the right channel.
@@ -89,6 +92,37 @@ interface PPB_AudioConfig {
       [in] uint32_t sample_frame_count);
 
   /**
+   * This comment block applies to version 1.0, which is deprecated in favor of
+   * the same function but with slightly different signature and behavior.
+   *
+   * RecommendSampleFrameCount() returns the supported sample frame count
+   * closest to the requested count. The sample frame count determines the
+   * overall latency of audio. Since one "frame" is always buffered in advance,
+   * smaller frame counts will yield lower latency, but higher CPU utilization.
+   * For best audio performance, use the value returned by RecommendSampleRate
+   * as the input sample rate, then use the RecommendSampleFrameCount return
+   * value when creating the audio configuration resource.
+   *
+   * Sample counts less than
+   * <code>PP_AUDIOMINSAMPLEFRAMECOUNT</code> and greater than
+   * <code>PP_AUDIOMAXSAMPLEFRAMECOUNT</code> are never supported on any
+   * system, but values in between aren't necessarily glitch-free.
+   *
+   * @param[in] sample_rate A <code>PP_AudioSampleRate</code> which is either
+   * <code>PP_AUDIOSAMPLERATE_44100</code> or
+   * <code>PP_AUDIOSAMPLERATE_48000.</code>
+   * @param[in] requested_sample_frame_count A <code>uint_32t</code> requested
+   * frame count.
+   *
+   * @return A <code>uint32_t</code> containing the recommended sample frame
+   * count if successful.
+   */
+  [deprecate=1.1]
+  uint32_t RecommendSampleFrameCount(
+      [in] PP_AudioSampleRate sample_rate,
+      [in] uint32_t requested_sample_frame_count);
+
+  /**
    * RecommendSampleFrameCount() returns the supported sample frame count
    * closest to the requested count. The sample frame count determines the
    * overall latency of audio. Since one "frame" is always buffered in advance,
@@ -102,6 +136,9 @@ interface PPB_AudioConfig {
    * system, but values in between aren't necessarily valid. This function
    * will return a supported count closest to the requested value.
    *
+   * RecommendSampleFrameCount() result is intended for audio output devices.
+   *
+   * @param[in] instance
    * @param[in] sample_rate A <code>PP_AudioSampleRate</code> which is either
    * <code>PP_AUDIOSAMPLERATE_44100</code> or
    * <code>PP_AUDIOSAMPLERATE_48000.</code>
@@ -111,7 +148,9 @@ interface PPB_AudioConfig {
    * @return A <code>uint32_t</code> containing the recommended sample frame
    * count if successful.
    */
+  [version=1.1]
   uint32_t RecommendSampleFrameCount(
+      [in] PP_Instance instance,
       [in] PP_AudioSampleRate sample_rate,
       [in] uint32_t requested_sample_frame_count);
 
@@ -155,5 +194,21 @@ interface PPB_AudioConfig {
    */
   uint32_t GetSampleFrameCount(
       [in] PP_Resource config);
+
+  /**
+   * RecommendSampleRate() returns the native sample rate that the browser
+   * is using in the backend.  Applications that use the recommended sample
+   * rate will have potentially better latency and fidelity.  The return value
+   * is indended for audio output devices.
+   *
+   * @param[in] instance
+   *
+   * @return A <code>uint32_t</code> containing the recommended sample frame
+   * count if successful.
+   */
+  [version=1.1]
+  PP_AudioSampleRate RecommendSampleRate(
+      [in] PP_Instance instance);
+
 };
 
diff --git a/ppapi/c/ppb_audio_config.h b/ppapi/c/ppb_audio_config.h
index 2b62c3d..22547ea 100644
--- a/ppapi/c/ppb_audio_config.h
+++ b/ppapi/c/ppb_audio_config.h
@@ -3,7 +3,7 @@
  * found in the LICENSE file.
  */
 
-/* From ppb_audio_config.idl modified Fri Jan 20 13:12:44 2012. */
+/* From ppb_audio_config.idl modified Thu Feb 16 16:23:46 2012. */
 
 #ifndef PPAPI_C_PPB_AUDIO_CONFIG_H_
 #define PPAPI_C_PPB_AUDIO_CONFIG_H_
@@ -15,7 +15,8 @@
 #include "ppapi/c/pp_stdint.h"
 
 #define PPB_AUDIO_CONFIG_INTERFACE_1_0 "PPB_AudioConfig;1.0"
-#define PPB_AUDIO_CONFIG_INTERFACE PPB_AUDIO_CONFIG_INTERFACE_1_0
+#define PPB_AUDIO_CONFIG_INTERFACE_1_1 "PPB_AudioConfig;1.1"
+#define PPB_AUDIO_CONFIG_INTERFACE PPB_AUDIO_CONFIG_INTERFACE_1_1
 
 /**
  * @file
@@ -68,12 +69,14 @@ PP_COMPILE_ASSERT_SIZE_IN_BYTES(PP_AudioSampleRate, 4);
  * <a href="/chrome/nativeclient/docs/audio.html">Pepper
  * Audio API</a> for information on using this interface.
  */
-struct PPB_AudioConfig_1_0 {
+struct PPB_AudioConfig_1_1 {
   /**
    * CreateStereo16bit() creates a 16 bit audio configuration resource. The
-   * <code>sample_frame_count</code> should be the result of calling
-   * <code>RecommendSampleFrameCount</code>. If the sample frame count or bit
-   * rate isn't supported, this function will fail and return a null resource.
+   * <code>sample_rate</code> should be the result of calling
+   * <code>RecommendSampleRate</code> and <code>sample_frame_count</code> should
+   * be the result of calling <code>RecommendSampleFrameCount</code>. If the
+   * sample frame count or bit rate isn't supported, this function will fail and
+   * return a null resource.
    *
    * A single sample frame on a stereo device means one value for the left
    * channel and one value for the right channel.
@@ -120,6 +123,9 @@ struct PPB_AudioConfig_1_0 {
    * system, but values in between aren't necessarily valid. This function
    * will return a supported count closest to the requested value.
    *
+   * RecommendSampleFrameCount() result is intended for audio output devices.
+   *
+   * @param[in] instance
    * @param[in] sample_rate A <code>PP_AudioSampleRate</code> which is either
    * <code>PP_AUDIOSAMPLERATE_44100</code> or
    * <code>PP_AUDIOSAMPLERATE_48000.</code>
@@ -130,6 +136,7 @@ struct PPB_AudioConfig_1_0 {
    * count if successful.
    */
   uint32_t (*RecommendSampleFrameCount)(
+      PP_Instance instance,
       PP_AudioSampleRate sample_rate,
       uint32_t requested_sample_frame_count);
   /**
@@ -167,9 +174,33 @@ struct PPB_AudioConfig_1_0 {
    * RecommendSampleFrameCount() for more on sample frame counts.
    */
   uint32_t (*GetSampleFrameCount)(PP_Resource config);
+  /**
+   * RecommendSampleRate() returns the native sample rate that the browser
+   * is using in the backend.  Applications that use the recommended sample
+   * rate will have potentially better latency and fidelity.  The return value
+   * is indended for audio output devices.
+   *
+   * @param[in] instance
+   *
+   * @return A <code>uint32_t</code> containing the recommended sample frame
+   * count if successful.
+   */
+  PP_AudioSampleRate (*RecommendSampleRate)(PP_Instance instance);
 };
 
-typedef struct PPB_AudioConfig_1_0 PPB_AudioConfig;
+typedef struct PPB_AudioConfig_1_1 PPB_AudioConfig;
+
+struct PPB_AudioConfig_1_0 {
+  PP_Resource (*CreateStereo16Bit)(PP_Instance instance,
+                                   PP_AudioSampleRate sample_rate,
+                                   uint32_t sample_frame_count);
+  uint32_t (*RecommendSampleFrameCount)(
+      PP_AudioSampleRate sample_rate,
+      uint32_t requested_sample_frame_count);
+  PP_Bool (*IsAudioConfig)(PP_Resource resource);
+  PP_AudioSampleRate (*GetSampleRate)(PP_Resource config);
+  uint32_t (*GetSampleFrameCount)(PP_Resource config);
+};
 /**
  * @}
  */
diff --git a/ppapi/cpp/audio_config.cc b/ppapi/cpp/audio_config.cc
index b553dad..a49515e 100644
--- a/ppapi/cpp/audio_config.cc
+++ b/ppapi/cpp/audio_config.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -36,13 +36,24 @@ AudioConfig::AudioConfig(Instance* instance,
 }
 
 // static
+PP_AudioSampleRate AudioConfig::RecommendSampleRate(Instance* instance) {
+  if (!has_interface<PPB_AudioConfig>())
+    return PP_AUDIOSAMPLERATE_NONE;
+  return get_interface<PPB_AudioConfig>()->
+      RecommendSampleRate(instance->pp_instance());
+}
+
+// static
 uint32_t AudioConfig::RecommendSampleFrameCount(
+    Instance* instance,
     PP_AudioSampleRate sample_rate,
     uint32_t requested_sample_frame_count) {
   if (!has_interface<PPB_AudioConfig>())
     return 0;
   return get_interface<PPB_AudioConfig>()->
-      RecommendSampleFrameCount(sample_rate, requested_sample_frame_count);
+      RecommendSampleFrameCount(instance->pp_instance(),
+                                sample_rate,
+                                requested_sample_frame_count);
 }
 
 }  // namespace pp
diff --git a/ppapi/cpp/audio_config.h b/ppapi/cpp/audio_config.h
index 2eac4d6..ff1d256 100644
--- a/ppapi/cpp/audio_config.h
+++ b/ppapi/cpp/audio_config.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -75,6 +75,11 @@ class AudioConfig : public Resource {
               PP_AudioSampleRate sample_rate,
               uint32_t sample_frame_count);
 
+  /// RecommendSampleRate() returns the native sample rate used by the
+  /// audio system.  Applications that use the recommended sample rate might
+  /// obtain lower latency and higher fidelity output.
+  static PP_AudioSampleRate RecommendSampleRate(Instance* instance);
+
   /// RecommendSampleFrameCount() returns a supported frame count closest to
   /// the requested count. The sample frame count determines the overall
   /// latency of audio. Smaller frame counts will yield lower latency, but
@@ -87,7 +92,9 @@ class AudioConfig : public Resource {
   /// will return a supported count closest to the requested value for use in
   /// the constructor.
   ///
- /// @param[in] sample_rate A <code>PP_AudioSampleRate</code> which is either
+  /// @param[in] instance A pointer to an <code>Instance</code> identifying
+  /// one instance of a module.
+  /// @param[in] sample_rate A <code>PP_AudioSampleRate</code> which is either
   /// <code>PP_AUDIOSAMPLERATE_44100</code> or
   /// <code>PP_AUDIOSAMPLERATE_48000</code>.
   /// @param[in] requested_sample_frame_count A uint_32t requested frame count.
@@ -96,6 +103,7 @@ class AudioConfig : public Resource {
   /// successful. If the sample frame count or bit rate is not supported,
   /// this function will fail and return 0.
   static uint32_t RecommendSampleFrameCount(
+      Instance* instance,
       PP_AudioSampleRate sample_rate,
       uint32_t requested_sample_frame_count);
 
diff --git a/ppapi/examples/audio/audio.cc b/ppapi/examples/audio/audio.cc
index 2c01faf..e6a0a84 100644
--- a/ppapi/examples/audio/audio.cc
+++ b/ppapi/examples/audio/audio.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -56,7 +56,7 @@ class MyInstance : public pp::Instance {
 
     pp::AudioConfig config;
     sample_count_ = pp::AudioConfig::RecommendSampleFrameCount(
-        sample_rate_, kDefaultSampleCount);
+        this, sample_rate_, kDefaultSampleCount);
     config = pp::AudioConfig(this, sample_rate_, sample_count_);
     audio_ = pp::Audio(this, config, SineWaveCallbackTrampoline, this);
     return audio_.StartPlayback();
diff --git a/ppapi/examples/audio_input/audio_input.cc b/ppapi/examples/audio_input/audio_input.cc
index 74bc08e..203718e 100644
--- a/ppapi/examples/audio_input/audio_input.cc
+++ b/ppapi/examples/audio_input/audio_input.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -41,7 +41,8 @@ class MyInstance : public pp::Instance {
     const uint32_t kSampleCount = 1024;
     const uint32_t kChannelCount = 1;
 
-    sample_count_ = pp::AudioConfig::RecommendSampleFrameCount(kSampleFrequency,
+    sample_count_ = pp::AudioConfig::RecommendSampleFrameCount(this,
+                                                               kSampleFrequency,
                                                                kSampleCount);
     PP_DCHECK(sample_count_ > 0);
     channel_count_ = kChannelCount;
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_audio_config_rpc_server.cc b/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_audio_config_rpc_server.cc
index 883331e..205cbf9 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_audio_config_rpc_server.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/browser_ppb_audio_config_rpc_server.cc
@@ -13,11 +13,18 @@
 
 using ppapi_proxy::DebugPrintf;
 
+static const PPB_AudioConfig_1_0* GetAudioConfigInterface_1_0() {
+  static const PPB_AudioConfig_1_0* audio_config =
+      static_cast<const PPB_AudioConfig_1_0*>
+          (ppapi_proxy::GetBrowserInterface(PPB_AUDIO_CONFIG_INTERFACE_1_0));
+  return audio_config;
+}
+
 static const PPB_AudioConfig* GetAudioConfigInterface() {
-  static const PPB_AudioConfig* audioConfig =
+  static const PPB_AudioConfig* audio_config =
       static_cast<const PPB_AudioConfig*>
           (ppapi_proxy::GetBrowserInterface(PPB_AUDIO_CONFIG_INTERFACE));
-  return audioConfig;
+  return audio_config;
 }
 
 void PpbAudioConfigRpcServer::PPB_AudioConfig_CreateStereo16Bit(
@@ -28,35 +35,64 @@ void PpbAudioConfigRpcServer::PPB_AudioConfig_CreateStereo16Bit(
     int32_t sample_frame_count,
     PP_Resource* resource) {
   NaClSrpcClosureRunner runner(done);
-  const PPB_AudioConfig* audio = GetAudioConfigInterface();
+  const PPB_AudioConfig* audio_config = GetAudioConfigInterface();
   rpc->result = NACL_SRPC_RESULT_APP_ERROR;
-  if (NULL == audio) {
+  if (NULL == audio_config) {
     return;
   }
   if (NULL == resource) {
     return;
   }
-  *resource = audio->CreateStereo16Bit(
+  *resource = audio_config->CreateStereo16Bit(
       instance, static_cast<PP_AudioSampleRate>(sample_rate),
       sample_frame_count);
   DebugPrintf("PPB_AudioConfig::CreateStereo16Bit: resource=%"NACL_PRId32"\n",
-              *resource);
+      *resource);
+  DebugPrintf(
+      "PPB_AudioConfig::CreateStereo16Bit: sample_rate=%"NACL_PRIu32"\n",
+      sample_rate);
+  DebugPrintf(
+      "PPB_AudioConfig::CreateStereo16Bit: frame_count=%"NACL_PRIu32"\n",
+      sample_frame_count);
+  rpc->result = NACL_SRPC_RESULT_OK;
+}
+
+// Preserve old behavior for applications that request 1.0 interface.
+void PpbAudioConfigRpcServer::PPB_AudioConfig_RecommendSampleFrameCount_1_0(
+    NaClSrpcRpc* rpc,
+    NaClSrpcClosure* done,
+    int32_t sample_rate,
+    int32_t request_sample_frame_count,
+    int32_t* sample_frame_count) {
+  NaClSrpcClosureRunner runner(done);
+  const PPB_AudioConfig_1_0* audio_config = GetAudioConfigInterface_1_0();
+  rpc->result = NACL_SRPC_RESULT_APP_ERROR;
+  if (NULL == audio_config) {
+    return;
+  }
+  *sample_frame_count = audio_config->RecommendSampleFrameCount(
+      static_cast<PP_AudioSampleRate>(sample_rate),
+      request_sample_frame_count);
+  DebugPrintf("PPB_AudioConfig::RecommendSampleFrameCount_1_0: "
+              "sample_frame_count=%"NACL_PRId32"\n", *sample_frame_count);
   rpc->result = NACL_SRPC_RESULT_OK;
 }
 
 void PpbAudioConfigRpcServer::PPB_AudioConfig_RecommendSampleFrameCount(
     NaClSrpcRpc* rpc,
     NaClSrpcClosure* done,
+    PP_Instance instance,
     int32_t sample_rate,
     int32_t request_sample_frame_count,
     int32_t* sample_frame_count) {
   NaClSrpcClosureRunner runner(done);
-  const PPB_AudioConfig* audio = GetAudioConfigInterface();
+  const PPB_AudioConfig* audio_config = GetAudioConfigInterface();
   rpc->result = NACL_SRPC_RESULT_APP_ERROR;
-  if (NULL == audio) {
+  if (NULL == audio_config) {
     return;
   }
-  *sample_frame_count = audio->RecommendSampleFrameCount(
+  *sample_frame_count = audio_config->RecommendSampleFrameCount(
+      instance,
       static_cast<PP_AudioSampleRate>(sample_rate),
       request_sample_frame_count);
   DebugPrintf("PPB_AudioConfig::RecommendSampleFrameCount: "
@@ -70,12 +106,12 @@ void PpbAudioConfigRpcServer::PPB_AudioConfig_IsAudioConfig(
     PP_Resource resource,
     int32_t* success) {
   NaClSrpcClosureRunner runner(done);
-  const PPB_AudioConfig* audio = GetAudioConfigInterface();
+  const PPB_AudioConfig* audio_config = GetAudioConfigInterface();
   rpc->result = NACL_SRPC_RESULT_APP_ERROR;
-  if (NULL == audio) {
+  if (NULL == audio_config) {
     return;
   }
-  PP_Bool pp_success = audio->IsAudioConfig(resource);
+  PP_Bool pp_success = audio_config->IsAudioConfig(resource);
   *success = PP_ToBool(pp_success);
   DebugPrintf("PPB_AudioConfig::IsAudioConfig: success=%d\n", *success);
   rpc->result = NACL_SRPC_RESULT_OK;
@@ -87,9 +123,9 @@ void PpbAudioConfigRpcServer::PPB_AudioConfig_GetSampleRate(
     PP_Resource resource,
     int32_t* sample_rate) {
   NaClSrpcClosureRunner runner(done);
-  const PPB_AudioConfig* audio = GetAudioConfigInterface();
+  const PPB_AudioConfig* audio_config = GetAudioConfigInterface();
   rpc->result = NACL_SRPC_RESULT_APP_ERROR;
-  if (NULL == audio) {
+  if (NULL == audio_config) {
     return;
   }
   if (ppapi_proxy::kInvalidResourceId == resource) {
@@ -98,7 +134,7 @@ void PpbAudioConfigRpcServer::PPB_AudioConfig_GetSampleRate(
   if (NULL == sample_rate) {
     return;
   }
-  *sample_rate = audio->GetSampleRate(resource);
+  *sample_rate = audio_config->GetSampleRate(resource);
   DebugPrintf("PPB_AudioConfig::GetSampleRate: pp_success=%"NACL_PRId32"\n",
               *sample_rate);
   rpc->result = NACL_SRPC_RESULT_OK;
@@ -110,9 +146,9 @@ void PpbAudioConfigRpcServer::PPB_AudioConfig_GetSampleFrameCount(
     PP_Resource resource,
     int32_t* sample_frame_count) {
   NaClSrpcClosureRunner runner(done);
-  const PPB_AudioConfig* audio = GetAudioConfigInterface();
+  const PPB_AudioConfig* audio_config = GetAudioConfigInterface();
   rpc->result = NACL_SRPC_RESULT_APP_ERROR;
-  if (NULL == audio) {
+  if (NULL == audio_config) {
     return;
   }
   if (ppapi_proxy::kInvalidResourceId == resource) {
@@ -121,8 +157,25 @@ void PpbAudioConfigRpcServer::PPB_AudioConfig_GetSampleFrameCount(
   if (NULL == sample_frame_count) {
     return;
   }
-  *sample_frame_count = audio->GetSampleFrameCount(resource);
+  *sample_frame_count = audio_config->GetSampleFrameCount(resource);
   DebugPrintf("PPB_AudioConfig::GetSampleFrameCount: "
               "sample_frame_count=%"NACL_PRId32"\n", *sample_frame_count);
   rpc->result = NACL_SRPC_RESULT_OK;
 }
+
+void PpbAudioConfigRpcServer::PPB_AudioConfig_RecommendSampleRate(
+    NaClSrpcRpc* rpc,
+    NaClSrpcClosure* done,
+    PP_Instance instance,
+    int32_t* sample_rate) {
+  NaClSrpcClosureRunner runner(done);
+  const PPB_AudioConfig* audio_config = GetAudioConfigInterface();
+  rpc->result = NACL_SRPC_RESULT_APP_ERROR;
+  if (NULL == audio_config) {
+    return;
+  }
+  *sample_rate = audio_config->RecommendSampleRate(instance);
+  DebugPrintf("PPB_AudioConfig::RecommendSampleRate: "
+              "sample_rate=%"NACL_PRIu32"\n", *sample_rate);
+  rpc->result = NACL_SRPC_RESULT_OK;
+}
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb.cc b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb.cc
index b33400c..c1314a0 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb.cc
@@ -58,6 +58,8 @@ struct InterfaceMapElement {
 InterfaceMapElement interface_map[] = {
   { PPB_AUDIO_INTERFACE, PluginAudio::GetInterface(), true },
   { PPB_AUDIO_CONFIG_INTERFACE, PluginAudioConfig::GetInterface(), true },
+  { PPB_AUDIO_CONFIG_INTERFACE_1_0, PluginAudioConfig::GetInterface1_0(),
+    true },
   { PPB_CORE_INTERFACE, PluginCore::GetInterface(), true },
   { PPB_CURSOR_CONTROL_DEV_INTERFACE, PluginCursorControl::GetInterface(),
     true },
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.cc b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.cc
index efd4cf9..5fa5188 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.cc
@@ -51,13 +51,33 @@ uint32_t GetSampleFrameCount(PP_Resource config) {
   return 0;
 }
 
-uint32_t RecommendSampleFrameCount(PP_AudioSampleRate sample_rate,
+uint32_t RecommendSampleFrameCount_1_0(PP_AudioSampleRate sample_rate,
+                                       uint32_t request_sample_frame_count) {
+  DebugPrintf("PPB_AudioConfig::RecommendSampleFrameCount_1_0");
+  int32_t out_sample_frame_count;
+  NaClSrpcError srpc_result =
+      PpbAudioConfigRpcClient::PPB_AudioConfig_RecommendSampleFrameCount_1_0(
+          GetMainSrpcChannel(),
+          static_cast<int32_t>(sample_rate),
+          static_cast<int32_t>(request_sample_frame_count),
+          &out_sample_frame_count);
+  DebugPrintf("PPB_AudioConfig::RecommendSampleFrameCount_1_0: %s\n",
+              NaClSrpcErrorString(srpc_result));
+  if (NACL_SRPC_RESULT_OK == srpc_result) {
+    return static_cast<uint32_t>(out_sample_frame_count);
+  }
+  return 0;
+}
+
+uint32_t RecommendSampleFrameCount(PP_Instance instance,
+                                   PP_AudioSampleRate sample_rate,
                                    uint32_t request_sample_frame_count) {
   DebugPrintf("PPB_AudioConfig::RecommendSampleFrameCount");
   int32_t out_sample_frame_count;
   NaClSrpcError srpc_result =
       PpbAudioConfigRpcClient::PPB_AudioConfig_RecommendSampleFrameCount(
           GetMainSrpcChannel(),
+          instance,
           static_cast<int32_t>(sample_rate),
           static_cast<int32_t>(request_sample_frame_count),
           &out_sample_frame_count);
@@ -106,6 +126,23 @@ PP_Resource CreateStereo16Bit(PP_Instance instance,
   }
   return kInvalidResourceId;
 }
+
+PP_AudioSampleRate RecommendSampleRate(PP_Instance instance) {
+  DebugPrintf("PPB_AudioConfig::RecommendSampleRate");
+  int32_t out_sample_rate;
+  NaClSrpcError srpc_result =
+      PpbAudioConfigRpcClient::PPB_AudioConfig_RecommendSampleRate(
+          GetMainSrpcChannel(),
+          instance,
+          &out_sample_rate);
+  DebugPrintf("PPB_AudioConfig::RecommendSampleRate: %s\n",
+              NaClSrpcErrorString(srpc_result));
+  if (NACL_SRPC_RESULT_OK == srpc_result) {
+    return static_cast<PP_AudioSampleRate>(out_sample_rate);
+  }
+  return PP_AUDIOSAMPLERATE_NONE;
+}
+
 }  // namespace
 
 const PPB_AudioConfig* PluginAudioConfig::GetInterface() {
@@ -115,7 +152,20 @@ const PPB_AudioConfig* PluginAudioConfig::GetInterface() {
     IsAudioConfig,
     GetSampleRate,
     GetSampleFrameCount,
+    RecommendSampleRate
   };
   return &audio_config_interface;
 }
+
+const PPB_AudioConfig_1_0* PluginAudioConfig::GetInterface1_0() {
+  static const PPB_AudioConfig_1_0 audio_config_interface = {
+    CreateStereo16Bit,
+    RecommendSampleFrameCount_1_0,
+    IsAudioConfig,
+    GetSampleRate,
+    GetSampleFrameCount
+  };
+  return &audio_config_interface;
+}
+
 }  // namespace ppapi_proxy
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.h b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.h
index 15a6579..0943383 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.h
+++ b/ppapi/native_client/src/shared/ppapi_proxy/plugin_ppb_audio_config.h
@@ -1,6 +1,6 @@
-// Copyright 2011 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.
+// Copyright (c) 2012 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.
 
 #ifndef NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_AUDIO_CONFIG_H_
 #define NATIVE_CLIENT_SRC_SHARED_PPAPI_PROXY_PLUGIN_AUDIO_CONFIG_H_
@@ -15,6 +15,8 @@ namespace ppapi_proxy {
 class PluginAudioConfig : public PluginResource {
  public:
   static const PPB_AudioConfig* GetInterface();
+  // Returns the 1.0 interface to support backwards-compatibility.
+  static const PPB_AudioConfig_1_0* GetInterface1_0();
 
  private:
   NACL_DISALLOW_COPY_AND_ASSIGN(PluginAudioConfig);
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/ppb_audio_config.srpc b/ppapi/native_client/src/shared/ppapi_proxy/ppb_audio_config.srpc
index 95a8a99..20d33c0 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/ppb_audio_config.srpc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/ppb_audio_config.srpc
@@ -1,4 +1,4 @@
-# Copyright (c) 2010 The Native Client Authors. All rights reserved.
+# Copyright (c) 2012 The Native Client Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -24,14 +24,23 @@
            'outputs': [['out_bool', 'int32_t']
                       ]
           },
-          # Implements a call to get recommended sample frame count.
-          {'name': 'PPB_AudioConfig_RecommendSampleFrameCount',
+          # Implements a call to get recommended sample frame count (v1.0)
+          {'name': 'PPB_AudioConfig_RecommendSampleFrameCount_1_0',
            'inputs': [['request_sample_rate', 'int32_t'],
                       ['request_sample_frame_count', 'int32_t'],
                      ],
            'outputs': [['out_sample_frame_count', 'int32_t']
                       ]
           },
+          # Implements a call to get recommended sample frame count
+          {'name': 'PPB_AudioConfig_RecommendSampleFrameCount',
+           'inputs': [['instance', 'PP_Instance'],
+                      ['request_sample_rate', 'int32_t'],
+                      ['request_sample_frame_count', 'int32_t'],
+                     ],
+           'outputs': [['out_sample_frame_count', 'int32_t']
+                      ]
+          },
           # Implements a call to get the sample rate.
           {'name': 'PPB_AudioConfig_GetSampleRate',
            'inputs': [['resource', 'PP_Resource'],
@@ -46,5 +55,12 @@
            'outputs': [['sample_frame_count', 'int32_t'],
                       ]
           },
+          # Implements a call to get recommended sample rate
+          {'name': 'PPB_AudioConfig_RecommendSampleRate',
+           'inputs': [['instance', 'PP_Instance'],
+                     ],
+           'outputs': [['sample_rate', 'int32_t']
+                      ]
+          },
          ]
 }
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_client.cc b/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_client.cc
index 68c19ab..3b72662 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_client.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_client.cc
@@ -201,8 +201,28 @@ NaClSrpcError PpbAudioConfigRpcClient::PPB_AudioConfig_IsAudioConfig(
   return retval;
 }
 
+NaClSrpcError PpbAudioConfigRpcClient::PPB_AudioConfig_RecommendSampleFrameCount_1_0(
+    NaClSrpcChannel* channel,
+    int32_t request_sample_rate,
+    int32_t request_sample_frame_count,
+    int32_t* out_sample_frame_count)  {
+  VCHECK(ppapi_proxy::PPBCoreInterface()->IsMainThread(),
+         ("%s: PPAPI calls are not supported off the main thread\n",
+          __FUNCTION__));
+  NaClSrpcError retval;
+  retval = NaClSrpcInvokeBySignature(
+      channel,
+      "PPB_AudioConfig_RecommendSampleFrameCount_1_0:ii:i",
+      request_sample_rate,
+      request_sample_frame_count,
+      out_sample_frame_count
+  );
+  return retval;
+}
+
 NaClSrpcError PpbAudioConfigRpcClient::PPB_AudioConfig_RecommendSampleFrameCount(
     NaClSrpcChannel* channel,
+    PP_Instance instance,
     int32_t request_sample_rate,
     int32_t request_sample_frame_count,
     int32_t* out_sample_frame_count)  {
@@ -212,7 +232,8 @@ NaClSrpcError PpbAudioConfigRpcClient::PPB_AudioConfig_RecommendSampleFrameCount
   NaClSrpcError retval;
   retval = NaClSrpcInvokeBySignature(
       channel,
-      "PPB_AudioConfig_RecommendSampleFrameCount:ii:i",
+      "PPB_AudioConfig_RecommendSampleFrameCount:iii:i",
+      instance,
       request_sample_rate,
       request_sample_frame_count,
       out_sample_frame_count
@@ -254,6 +275,23 @@ NaClSrpcError PpbAudioConfigRpcClient::PPB_AudioConfig_GetSampleFrameCount(
   return retval;
 }
 
+NaClSrpcError PpbAudioConfigRpcClient::PPB_AudioConfig_RecommendSampleRate(
+    NaClSrpcChannel* channel,
+    PP_Instance instance,
+    int32_t* sample_rate)  {
+  VCHECK(ppapi_proxy::PPBCoreInterface()->IsMainThread(),
+         ("%s: PPAPI calls are not supported off the main thread\n",
+          __FUNCTION__));
+  NaClSrpcError retval;
+  retval = NaClSrpcInvokeBySignature(
+      channel,
+      "PPB_AudioConfig_RecommendSampleRate:i:i",
+      instance,
+      sample_rate
+  );
+  return retval;
+}
+
 NaClSrpcError PpbCoreRpcClient::PPB_Core_AddRefResource(
     NaClSrpcChannel* channel,
     PP_Resource resource)  {
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_server.cc b/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_server.cc
index 91fdd0d..3e2a497 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_server.cc
+++ b/ppapi/native_client/src/shared/ppapi_proxy/ppb_rpc_server.cc
@@ -169,6 +169,21 @@ static void PPB_AudioConfig_IsAudioConfigDispatcher(
   );
 }
 
+static void PPB_AudioConfig_RecommendSampleFrameCount_1_0Dispatcher(
+    NaClSrpcRpc* rpc,
+    NaClSrpcArg** inputs,
+    NaClSrpcArg** outputs,
+    NaClSrpcClosure* done
+) {
+  PpbAudioConfigRpcServer::PPB_AudioConfig_RecommendSampleFrameCount_1_0(
+      rpc,
+      done,
+      inputs[0]->u.ival,
+      inputs[1]->u.ival,
+      &(outputs[0]->u.ival)
+  );
+}
+
 static void PPB_AudioConfig_RecommendSampleFrameCountDispatcher(
     NaClSrpcRpc* rpc,
     NaClSrpcArg** inputs,
@@ -180,6 +195,7 @@ static void PPB_AudioConfig_RecommendSampleFrameCountDispatcher(
       done,
       inputs[0]->u.ival,
       inputs[1]->u.ival,
+      inputs[2]->u.ival,
       &(outputs[0]->u.ival)
   );
 }
@@ -212,6 +228,20 @@ static void PPB_AudioConfig_GetSampleFrameCountDispatcher(
   );
 }
 
+static void PPB_AudioConfig_RecommendSampleRateDispatcher(
+    NaClSrpcRpc* rpc,
+    NaClSrpcArg** inputs,
+    NaClSrpcArg** outputs,
+    NaClSrpcClosure* done
+) {
+  PpbAudioConfigRpcServer::PPB_AudioConfig_RecommendSampleRate(
+      rpc,
+      done,
+      inputs[0]->u.ival,
+      &(outputs[0]->u.ival)
+  );
+}
+
 static void PPB_Core_AddRefResourceDispatcher(
     NaClSrpcRpc* rpc,
     NaClSrpcArg** inputs,
@@ -2922,9 +2952,11 @@ NaClSrpcHandlerDesc PpbRpcs::srpc_methods[] = {
   { "PPB_Audio_StartPlayback:i:i", PPB_Audio_StartPlaybackDispatcher },
   { "PPB_AudioConfig_CreateStereo16Bit:iii:i", PPB_AudioConfig_CreateStereo16BitDispatcher },
   { "PPB_AudioConfig_IsAudioConfig:i:i", PPB_AudioConfig_IsAudioConfigDispatcher },
-  { "PPB_AudioConfig_RecommendSampleFrameCount:ii:i", PPB_AudioConfig_RecommendSampleFrameCountDispatcher },
+  { "PPB_AudioConfig_RecommendSampleFrameCount_1_0:ii:i", PPB_AudioConfig_RecommendSampleFrameCount_1_0Dispatcher },
+  { "PPB_AudioConfig_RecommendSampleFrameCount:iii:i", PPB_AudioConfig_RecommendSampleFrameCountDispatcher },
   { "PPB_AudioConfig_GetSampleRate:i:i", PPB_AudioConfig_GetSampleRateDispatcher },
   { "PPB_AudioConfig_GetSampleFrameCount:i:i", PPB_AudioConfig_GetSampleFrameCountDispatcher },
+  { "PPB_AudioConfig_RecommendSampleRate:i:i", PPB_AudioConfig_RecommendSampleRateDispatcher },
   { "PPB_Core_AddRefResource:i:", PPB_Core_AddRefResourceDispatcher },
   { "PPB_Core_ReleaseResource:i:", PPB_Core_ReleaseResourceDispatcher },
   { "ReleaseResourceMultipleTimes:ii:", ReleaseResourceMultipleTimesDispatcher },
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/trusted/srpcgen/ppb_rpc.h b/ppapi/native_client/src/shared/ppapi_proxy/trusted/srpcgen/ppb_rpc.h
index c0e96ee..3d25c00 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/trusted/srpcgen/ppb_rpc.h
+++ b/ppapi/native_client/src/shared/ppapi_proxy/trusted/srpcgen/ppb_rpc.h
@@ -103,9 +103,16 @@ class PpbAudioConfigRpcServer {
       NaClSrpcClosure* done,
       PP_Resource resource,
       int32_t* out_bool);
+  static void PPB_AudioConfig_RecommendSampleFrameCount_1_0(
+      NaClSrpcRpc* rpc,
+      NaClSrpcClosure* done,
+      int32_t request_sample_rate,
+      int32_t request_sample_frame_count,
+      int32_t* out_sample_frame_count);
   static void PPB_AudioConfig_RecommendSampleFrameCount(
       NaClSrpcRpc* rpc,
       NaClSrpcClosure* done,
+      PP_Instance instance,
       int32_t request_sample_rate,
       int32_t request_sample_frame_count,
       int32_t* out_sample_frame_count);
@@ -119,6 +126,11 @@ class PpbAudioConfigRpcServer {
       NaClSrpcClosure* done,
       PP_Resource resource,
       int32_t* sample_frame_count);
+  static void PPB_AudioConfig_RecommendSampleRate(
+      NaClSrpcRpc* rpc,
+      NaClSrpcClosure* done,
+      PP_Instance instance,
+      int32_t* sample_rate);
 
  private:
   PpbAudioConfigRpcServer();
diff --git a/ppapi/native_client/src/shared/ppapi_proxy/untrusted/srpcgen/ppb_rpc.h b/ppapi/native_client/src/shared/ppapi_proxy/untrusted/srpcgen/ppb_rpc.h
index 1f3b993..e61f756 100644
--- a/ppapi/native_client/src/shared/ppapi_proxy/untrusted/srpcgen/ppb_rpc.h
+++ b/ppapi/native_client/src/shared/ppapi_proxy/untrusted/srpcgen/ppb_rpc.h
@@ -93,8 +93,14 @@ class PpbAudioConfigRpcClient {
       NaClSrpcChannel* channel,
       PP_Resource resource,
       int32_t* out_bool);
+  static NaClSrpcError PPB_AudioConfig_RecommendSampleFrameCount_1_0(
+      NaClSrpcChannel* channel,
+      int32_t request_sample_rate,
+      int32_t request_sample_frame_count,
+      int32_t* out_sample_frame_count);
   static NaClSrpcError PPB_AudioConfig_RecommendSampleFrameCount(
       NaClSrpcChannel* channel,
+      PP_Instance instance,
       int32_t request_sample_rate,
       int32_t request_sample_frame_count,
       int32_t* out_sample_frame_count);
@@ -106,6 +112,10 @@ class PpbAudioConfigRpcClient {
       NaClSrpcChannel* channel,
       PP_Resource resource,
       int32_t* sample_frame_count);
+  static NaClSrpcError PPB_AudioConfig_RecommendSampleRate(
+      NaClSrpcChannel* channel,
+      PP_Instance instance,
+      int32_t* sample_rate);
 
  private:
   PpbAudioConfigRpcClient();
diff --git a/ppapi/native_client/tests/ppapi_example_audio/audio.cc b/ppapi/native_client/tests/ppapi_example_audio/audio.cc
index 8b2fe25..ea214ba 100644
--- a/ppapi/native_client/tests/ppapi_example_audio/audio.cc
+++ b/ppapi/native_client/tests/ppapi_example_audio/audio.cc
@@ -35,12 +35,6 @@ const double kDefaultFrequencyLeft = 400.0;
 const double kDefaultFrequencyRight = 1000.0;
 const uint32_t kDefaultDuration = 10000;
 
-// This sample frequency is guaranteed to work.
-const PP_AudioSampleRate kSampleFrequency = PP_AUDIOSAMPLERATE_44100;
-// Buffer size in units of sample frames.
-// 4096 is a conservative size that should avoid underruns on most systems.
-const uint32_t kSampleFrameCount = 4096;
-
 const double kPi = 3.141592653589;
 const double kTwoPi = 2.0 * kPi;
 
@@ -198,11 +192,13 @@ class MyInstance : public pp::Instance {
   }
 
   virtual bool Init(uint32_t argc, const char* argn[], const char* argv[]) {
+    const int32_t kSampleFrameCount = 2048;
     ParseArgs(argc, argn, argv);
+    obtained_sample_rate_ = pp::AudioConfig::RecommendSampleRate(this);
     obtained_sample_frame_count_ = pp::AudioConfig::RecommendSampleFrameCount(
-        kSampleFrequency, kSampleFrameCount);
-    config_ = new
-       pp::AudioConfig(this, kSampleFrequency, obtained_sample_frame_count_);
+        this, obtained_sample_rate_, kSampleFrameCount);
+    config_ = new pp::AudioConfig(
+        this, obtained_sample_rate_, obtained_sample_frame_count_);
     CHECK(NULL != config_);
     audio_ = new pp::Audio(this, *config_, SineWaveCallback, this);
     CHECK(NULL != audio_);
@@ -214,8 +210,10 @@ class MyInstance : public pp::Instance {
  private:
   static void SineWaveCallback(void* samples, uint32_t num_bytes, void* thiz) {
     MyInstance* instance = reinterpret_cast<MyInstance*>(thiz);
-    const double delta_l = kTwoPi * instance->frequency_l_ / kSampleFrequency;
-    const double delta_r = kTwoPi * instance->frequency_r_ / kSampleFrequency;
+    const double delta_l = kTwoPi * instance->frequency_l_ /
+                           instance->obtained_sample_rate_;
+    const double delta_r = kTwoPi * instance->frequency_r_ /
+                           instance->obtained_sample_rate_;
 
     // Verify num_bytes and obtained_sample_frame_count match up.
     const int kNumChannelsForStereo = 2;
@@ -277,6 +275,7 @@ class MyInstance : public pp::Instance {
   bool stress_tests_;
 
   uint32_t duration_msec_;
+  PP_AudioSampleRate obtained_sample_rate_;
   uint32_t obtained_sample_frame_count_;
 
   int callback_count_;
diff --git a/ppapi/proxy/ppapi_messages.h b/ppapi/proxy/ppapi_messages.h
index 1f47a17..7a37f08 100644
--- a/ppapi/proxy/ppapi_messages.h
+++ b/ppapi/proxy/ppapi_messages.h
@@ -923,6 +923,14 @@ IPC_SYNC_MESSAGE_ROUTED2_1(PpapiHostMsg_PPBInstance_BindGraphics,
                            PP_Instance /* instance */,
                            ppapi::HostResource /* device */,
                            PP_Bool /* result */)
+IPC_SYNC_MESSAGE_ROUTED1_1(
+    PpapiHostMsg_PPBInstance_GetAudioHardwareOutputSampleRate,
+                           PP_Instance /* instance */,
+                           uint32_t /* result */)
+IPC_SYNC_MESSAGE_ROUTED1_1(
+    PpapiHostMsg_PPBInstance_GetAudioHardwareOutputBufferSize,
+                           PP_Instance /* instance */,
+                           uint32_t /* result */)
 IPC_SYNC_MESSAGE_ROUTED1_1(PpapiHostMsg_PPBInstance_IsFullFrame,
                            PP_Instance /* instance */,
                            PP_Bool /* result */)
diff --git a/ppapi/proxy/ppb_instance_proxy.cc b/ppapi/proxy/ppb_instance_proxy.cc
index 5bdde43..1f71e87 100644
--- a/ppapi/proxy/ppb_instance_proxy.cc
+++ b/ppapi/proxy/ppb_instance_proxy.cc
@@ -6,6 +6,7 @@
 
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_var.h"
+#include "ppapi/c/ppb_audio_config.h"
 #include "ppapi/c/ppb_instance.h"
 #include "ppapi/c/ppb_messaging.h"
 #include "ppapi/c/ppb_mouse_lock.h"
@@ -82,6 +83,12 @@ bool PPB_Instance_Proxy::OnMessageReceived(const IPC::Message& msg) {
                         OnHostMsgBindGraphics)
     IPC_MESSAGE_HANDLER(PpapiHostMsg_PPBInstance_IsFullFrame,
                         OnHostMsgIsFullFrame)
+    IPC_MESSAGE_HANDLER(
+        PpapiHostMsg_PPBInstance_GetAudioHardwareOutputSampleRate,
+        OnHostMsgGetAudioHardwareOutputSampleRate)
+    IPC_MESSAGE_HANDLER(
+        PpapiHostMsg_PPBInstance_GetAudioHardwareOutputBufferSize,
+        OnHostMsgGetAudioHardwareOutputBufferSize)
     IPC_MESSAGE_HANDLER(PpapiHostMsg_PPBInstance_ExecuteScript,
                         OnHostMsgExecuteScript)
     IPC_MESSAGE_HANDLER(PpapiHostMsg_PPBInstance_GetDefaultCharSet,
@@ -185,6 +192,24 @@ PP_Var PPB_Instance_Proxy::ExecuteScript(PP_Instance instance,
   return result.Return(dispatcher());
 }
 
+uint32_t PPB_Instance_Proxy::GetAudioHardwareOutputSampleRate(
+    PP_Instance instance) {
+  uint32_t result = PP_AUDIOSAMPLERATE_NONE;
+  dispatcher()->Send(
+      new PpapiHostMsg_PPBInstance_GetAudioHardwareOutputSampleRate(
+          API_ID_PPB_INSTANCE, instance, &result));
+  return result;
+}
+
+uint32_t PPB_Instance_Proxy::GetAudioHardwareOutputBufferSize(
+    PP_Instance instance) {
+  uint32_t result = 0;
+  dispatcher()->Send(
+      new PpapiHostMsg_PPBInstance_GetAudioHardwareOutputBufferSize(
+          API_ID_PPB_INSTANCE, instance, &result));
+  return result;
+}
+
 PP_Var PPB_Instance_Proxy::GetDefaultCharSet(PP_Instance instance) {
   PluginDispatcher* dispatcher = PluginDispatcher::GetForInstance(instance);
   if (!dispatcher)
@@ -421,6 +446,20 @@ void PPB_Instance_Proxy::OnHostMsgBindGraphics(PP_Instance instance,
   }
 }
 
+void PPB_Instance_Proxy::OnHostMsgGetAudioHardwareOutputSampleRate(
+    PP_Instance instance, uint32_t* result) {
+  EnterInstanceNoLock enter(instance, false);
+  if (enter.succeeded())
+    *result = enter.functions()->GetAudioHardwareOutputSampleRate(instance);
+}
+
+void PPB_Instance_Proxy::OnHostMsgGetAudioHardwareOutputBufferSize(
+    PP_Instance instance, uint32_t* result) {
+  EnterInstanceNoLock enter(instance, false);
+  if (enter.succeeded())
+    *result = enter.functions()->GetAudioHardwareOutputBufferSize(instance);
+}
+
 void PPB_Instance_Proxy::OnHostMsgIsFullFrame(PP_Instance instance,
                                               PP_Bool* result) {
   EnterInstanceNoLock enter(instance, false);
diff --git a/ppapi/proxy/ppb_instance_proxy.h b/ppapi/proxy/ppb_instance_proxy.h
index ba6b2ae..80927a3 100644
--- a/ppapi/proxy/ppb_instance_proxy.h
+++ b/ppapi/proxy/ppb_instance_proxy.h
@@ -52,6 +52,10 @@ class PPB_Instance_Proxy : public InterfaceProxy,
   virtual PP_Var ExecuteScript(PP_Instance instance,
                                PP_Var script,
                                PP_Var* exception) OVERRIDE;
+  virtual uint32_t GetAudioHardwareOutputSampleRate(PP_Instance instance)
+      OVERRIDE;
+  virtual uint32_t GetAudioHardwareOutputBufferSize(PP_Instance instance)
+      OVERRIDE;
   virtual PP_Var GetDefaultCharSet(PP_Instance instance) OVERRIDE;
   virtual void NumberOfFindResultsChanged(PP_Instance instance,
                                           int32_t total,
@@ -113,6 +117,10 @@ class PPB_Instance_Proxy : public InterfaceProxy,
                               SerializedVarReceiveInput script,
                               SerializedVarOutParam out_exception,
                               SerializedVarReturnValue result);
+  void OnHostMsgGetAudioHardwareOutputSampleRate(PP_Instance instance,
+                                                 uint32_t *result);
+  void OnHostMsgGetAudioHardwareOutputBufferSize(PP_Instance instance,
+                                                 uint32_t *result);
   void OnHostMsgGetDefaultCharSet(PP_Instance instance,
                                   SerializedVarReturnValue result);
   void OnHostMsgSetFullscreen(PP_Instance instance,
diff --git a/ppapi/shared_impl/ppb_audio_config_shared.cc b/ppapi/shared_impl/ppb_audio_config_shared.cc
index a866d79..a88b851 100644
--- a/ppapi/shared_impl/ppb_audio_config_shared.cc
+++ b/ppapi/shared_impl/ppb_audio_config_shared.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "ppapi/shared_impl/ppb_audio_config_shared.h"
+#include "ppapi/thunk/enter.h"
 
 namespace ppapi {
 
@@ -28,6 +29,76 @@ PP_Resource PPB_AudioConfig_Shared::Create(
   return object->GetReference();
 }
 
+// static
+uint32_t PPB_AudioConfig_Shared::RecommendSampleFrameCount_1_0(
+    PP_AudioSampleRate sample_rate,
+    uint32_t requested_sample_frame_count) {
+  // Version 1.0: Don't actually query to get a value from the
+  // hardware; instead return the input for in-range values.
+  if (requested_sample_frame_count < PP_AUDIOMINSAMPLEFRAMECOUNT)
+    return PP_AUDIOMINSAMPLEFRAMECOUNT;
+  if (requested_sample_frame_count > PP_AUDIOMAXSAMPLEFRAMECOUNT)
+    return PP_AUDIOMAXSAMPLEFRAMECOUNT;
+  return requested_sample_frame_count;
+}
+
+// static
+uint32_t PPB_AudioConfig_Shared::RecommendSampleFrameCount_1_1(
+    PP_Instance instance,
+    PP_AudioSampleRate sample_rate,
+    uint32_t sample_frame_count) {
+  // Version 1.1: Query the back-end hardware for sample rate and buffer size,
+  // and recommend a best fit based on request.
+  thunk::EnterInstance enter(instance);
+  if (enter.failed())
+    return 0;
+
+  // Get the hardware config.
+  PP_AudioSampleRate hardware_sample_rate = static_cast<PP_AudioSampleRate>(
+      enter.functions()->GetAudioHardwareOutputSampleRate(instance));
+  uint32_t hardware_sample_frame_count =
+      enter.functions()->GetAudioHardwareOutputBufferSize(instance);
+  if (sample_frame_count < PP_AUDIOMINSAMPLEFRAMECOUNT)
+    sample_frame_count = PP_AUDIOMINSAMPLEFRAMECOUNT;
+
+  // If client is using same sample rate as audio hardware, then recommend a
+  // multiple of the audio hardware's sample frame count.
+  if (hardware_sample_rate == sample_rate && hardware_sample_frame_count > 0) {
+    // Round up input sample_frame_count to nearest multiple.
+    uint32_t multiple = (sample_frame_count + hardware_sample_frame_count - 1) /
+        hardware_sample_frame_count;
+    uint32_t recommendation = hardware_sample_frame_count * multiple;
+    if (recommendation > PP_AUDIOMAXSAMPLEFRAMECOUNT)
+      recommendation = PP_AUDIOMAXSAMPLEFRAMECOUNT;
+    return recommendation;
+  }
+
+  // Otherwise, recommend a conservative 30ms buffer based on sample rate.
+  const uint32_t kDefault30msAt44100kHz = 1323;
+  const uint32_t kDefault30msAt48000kHz = 1440;
+  switch (sample_rate) {
+    case PP_AUDIOSAMPLERATE_44100:
+      return kDefault30msAt44100kHz;
+    case PP_AUDIOSAMPLERATE_48000:
+      return kDefault30msAt48000kHz;
+    case PP_AUDIOSAMPLERATE_NONE:
+      return 0;
+  }
+  // Unable to make a recommendation.
+  return 0;
+}
+
+// static
+PP_AudioSampleRate PPB_AudioConfig_Shared::RecommendSampleRate(
+    PP_Instance instance) {
+  thunk::EnterInstance enter(instance);
+  if (enter.failed())
+    return PP_AUDIOSAMPLERATE_NONE;
+  PP_AudioSampleRate hardware_sample_rate = static_cast<PP_AudioSampleRate>(
+    enter.functions()->GetAudioHardwareOutputSampleRate(instance));
+  return hardware_sample_rate;
+}
+
 thunk::PPB_AudioConfig_API* PPB_AudioConfig_Shared::AsPPB_AudioConfig_API() {
   return this;
 }
diff --git a/ppapi/shared_impl/ppb_audio_config_shared.h b/ppapi/shared_impl/ppb_audio_config_shared.h
index 410a32a8b..0174666 100644
--- a/ppapi/shared_impl/ppb_audio_config_shared.h
+++ b/ppapi/shared_impl/ppb_audio_config_shared.h
@@ -22,6 +22,12 @@ class PPAPI_SHARED_EXPORT PPB_AudioConfig_Shared
                             PP_Instance instance,
                             PP_AudioSampleRate sample_rate,
                             uint32_t sample_frame_count);
+  static uint32_t RecommendSampleFrameCount_1_0(PP_AudioSampleRate sample_rate,
+      uint32_t request_sample_frame_count);
+  static uint32_t RecommendSampleFrameCount_1_1(PP_Instance instance,
+      PP_AudioSampleRate sample_rate,
+      uint32_t request_sample_frame_count);
+  static PP_AudioSampleRate RecommendSampleRate(PP_Instance);
 
   // Resource overrides.
   virtual thunk::PPB_AudioConfig_API* AsPPB_AudioConfig_API() OVERRIDE;
diff --git a/ppapi/tests/test_audio.cc b/ppapi/tests/test_audio.cc
index 91c4d6d..b69ef4e 100644
--- a/ppapi/tests/test_audio.cc
+++ b/ppapi/tests/test_audio.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -64,7 +64,7 @@ std::string TestAudio::TestCreation() {
       // Make a config, create the audio resource, and release the config.
       uint32_t request_frame_count = kRequestFrameCounts[j];
       uint32_t frame_count = audio_config_interface_->RecommendSampleFrameCount(
-          sample_rate, request_frame_count);
+          instance_->pp_instance(), sample_rate, request_frame_count);
       PP_Resource ac = audio_config_interface_->CreateStereo16Bit(
           instance_->pp_instance(), sample_rate, frame_count);
       ASSERT_TRUE(ac);
@@ -106,7 +106,7 @@ std::string TestAudio::TestDestroyNoStop() {
   const uint32_t kRequestFrameCount = 2048;
 
   uint32_t frame_count = audio_config_interface_->RecommendSampleFrameCount(
-      kSampleRate, kRequestFrameCount);
+      instance_->pp_instance(), kSampleRate, kRequestFrameCount);
   PP_Resource ac = audio_config_interface_->CreateStereo16Bit(
       instance_->pp_instance(), kSampleRate, frame_count);
   ASSERT_TRUE(ac);
@@ -133,7 +133,7 @@ std::string TestAudio::TestFailures() {
 
   // We want a valid config for some of our tests of |Create()|.
   uint32_t frame_count = audio_config_interface_->RecommendSampleFrameCount(
-      kSampleRate, kRequestFrameCount);
+      instance_->pp_instance(), kSampleRate, kRequestFrameCount);
   PP_Resource ac = audio_config_interface_->CreateStereo16Bit(
       instance_->pp_instance(), kSampleRate, frame_count);
   ASSERT_TRUE(ac);
diff --git a/ppapi/tests/test_audio_config.cc b/ppapi/tests/test_audio_config.cc
index 79e847ff..902fc61 100644
--- a/ppapi/tests/test_audio_config.cc
+++ b/ppapi/tests/test_audio_config.cc
@@ -1,4 +1,4 @@
-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Copyright (c) 2012 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.
 
@@ -48,7 +48,7 @@ std::string TestAudioConfig::TestValidConfigs() {
       ASSERT_TRUE(request_frame_count <= PP_AUDIOMAXSAMPLEFRAMECOUNT);
 
       uint32_t frame_count = audio_config_interface_->RecommendSampleFrameCount(
-          sample_rate, request_frame_count);
+          instance_->pp_instance(), sample_rate, request_frame_count);
       ASSERT_TRUE(frame_count >= PP_AUDIOMINSAMPLEFRAMECOUNT);
       ASSERT_TRUE(frame_count <= PP_AUDIOMAXSAMPLEFRAMECOUNT);
 
diff --git a/ppapi/thunk/interfaces_ppb_public_stable.h b/ppapi/thunk/interfaces_ppb_public_stable.h
index 5bf22de..d8a3f03 100644
--- a/ppapi/thunk/interfaces_ppb_public_stable.h
+++ b/ppapi/thunk/interfaces_ppb_public_stable.h
@@ -49,6 +49,7 @@ PROXIED_API(PPB_URLResponseInfo)
 PROXIED_IFACE(PPB_Audio, PPB_AUDIO_INTERFACE_1_0, PPB_Audio_1_0)
 // This has no corresponding _Proxy object since it does no IPC.
 PROXIED_IFACE(NoAPIName, PPB_AUDIO_CONFIG_INTERFACE_1_0, PPB_AudioConfig_1_0)
+PROXIED_IFACE(NoAPIName, PPB_AUDIO_CONFIG_INTERFACE_1_1, PPB_AudioConfig_1_1)
 // Note: Core is special and is registered manually.
 PROXIED_IFACE(PPB_FileIO, PPB_FILEIO_INTERFACE_1_0, PPB_FileIO_1_0)
 PROXIED_IFACE(PPB_FileRef, PPB_FILEREF_INTERFACE_1_0, PPB_FileRef_1_0)
diff --git a/ppapi/thunk/ppb_audio_config_thunk.cc b/ppapi/thunk/ppb_audio_config_thunk.cc
index 2cc82a3..123d148 100644
--- a/ppapi/thunk/ppb_audio_config_thunk.cc
+++ b/ppapi/thunk/ppb_audio_config_thunk.cc
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "ppapi/shared_impl/ppb_audio_config_shared.h"
 #include "ppapi/thunk/thunk.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/ppb_audio_config_api.h"
@@ -22,17 +23,23 @@ PP_Resource CreateStereo16bit(PP_Instance instance,
                                               sample_frame_count);
 }
 
-uint32_t RecommendSampleFrameCount(PP_AudioSampleRate sample_rate,
-                                   uint32_t requested_sample_frame_count) {
-  // TODO(brettw) Currently we don't actually query to get a value from the
-  // hardware, so we always return the input for in-range values.
-  if (requested_sample_frame_count < PP_AUDIOMINSAMPLEFRAMECOUNT)
-    return PP_AUDIOMINSAMPLEFRAMECOUNT;
-  if (requested_sample_frame_count > PP_AUDIOMAXSAMPLEFRAMECOUNT)
-    return PP_AUDIOMAXSAMPLEFRAMECOUNT;
-  return requested_sample_frame_count;
+uint32_t RecommendSampleFrameCount_1_0(PP_AudioSampleRate sample_rate,
+                                       uint32_t requested_sample_frame_count) {
+  return PPB_AudioConfig_Shared::RecommendSampleFrameCount_1_0(sample_rate,
+      requested_sample_frame_count);
 }
 
+uint32_t RecommendSampleFrameCount_1_1(PP_Instance instance,
+                                       PP_AudioSampleRate sample_rate,
+                                       uint32_t requested_sample_frame_count) {
+  EnterInstance enter(instance);
+  if (enter.failed())
+    return 0;
+  return PPB_AudioConfig_Shared::RecommendSampleFrameCount_1_1(instance,
+      sample_rate, requested_sample_frame_count);
+}
+
+
 PP_Bool IsAudioConfig(PP_Resource resource) {
   EnterResource<PPB_AudioConfig_API> enter(resource, false);
   return PP_FromBool(enter.succeeded());
@@ -52,18 +59,39 @@ uint32_t GetSampleFrameCount(PP_Resource config_id) {
   return enter.object()->GetSampleFrameCount();
 }
 
-const PPB_AudioConfig g_ppb_audio_config_thunk = {
+PP_AudioSampleRate RecommendSampleRate(PP_Instance instance) {
+  EnterInstance enter(instance);
+  if (enter.failed())
+    return PP_AUDIOSAMPLERATE_NONE;
+  return PPB_AudioConfig_Shared::RecommendSampleRate(instance);
+}
+
+const PPB_AudioConfig_1_0 g_ppb_audio_config_thunk_1_0 = {
   &CreateStereo16bit,
-  &RecommendSampleFrameCount,
+  &RecommendSampleFrameCount_1_0,
   &IsAudioConfig,
   &GetSampleRate,
   &GetSampleFrameCount
 };
 
+const PPB_AudioConfig_1_1 g_ppb_audio_config_thunk_1_1 = {
+  &CreateStereo16bit,
+  &RecommendSampleFrameCount_1_1,
+  &IsAudioConfig,
+  &GetSampleRate,
+  &GetSampleFrameCount,
+  &RecommendSampleRate
+};
+
+
 }  // namespace
 
 const PPB_AudioConfig_1_0* GetPPB_AudioConfig_1_0_Thunk() {
-  return &g_ppb_audio_config_thunk;
+  return &g_ppb_audio_config_thunk_1_0;
+}
+
+const PPB_AudioConfig_1_1* GetPPB_AudioConfig_1_1_Thunk() {
+  return &g_ppb_audio_config_thunk_1_1;
 }
 
 }  // namespace thunk
diff --git a/ppapi/thunk/ppb_instance_api.h b/ppapi/thunk/ppb_instance_api.h
index 741f762..3055d73 100644
--- a/ppapi/thunk/ppb_instance_api.h
+++ b/ppapi/thunk/ppb_instance_api.h
@@ -9,6 +9,7 @@
 #include "ppapi/c/dev/ppb_gamepad_dev.h"
 #include "ppapi/c/dev/ppb_url_util_dev.h"
 #include "ppapi/c/pp_completion_callback.h"
+#include "ppapi/c/ppb_audio_config.h"
 #include "ppapi/c/ppb_instance.h"
 #include "ppapi/c/pp_bool.h"
 #include "ppapi/c/pp_size.h"
@@ -43,6 +44,10 @@ class PPB_Instance_FunctionAPI {
                                PP_Var script,
                                PP_Var* exception) = 0;
 
+  // Audio.
+  virtual uint32_t GetAudioHardwareOutputSampleRate(PP_Instance instance) = 0;
+  virtual uint32_t GetAudioHardwareOutputBufferSize(PP_Instance instance) = 0;
+
   // CharSet.
   virtual PP_Var GetDefaultCharSet(PP_Instance instance) = 0;