[PPAPI] API definition for audio media stream artifacts

ppapi/api/ppb_audio_frame.idl

Index: ppapi/api/ppb_audio_frame.idl
diff --git a/ppapi/api/ppb_audio_frame.idl b/ppapi/api/ppb_audio_frame.idl
new file mode 100644
index 0000000000000000000000000000000000000000..8d6722f73a9ca679a4321144286a3aca349a6a55
--- /dev/null
+++ b/ppapi/api/ppb_audio_frame.idl
@@ -0,0 +1,99 @@
+/* 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.
+ */
+
+/**
+ * Defines the <code>PPB_AudioFrame</code> interface.
+ */
+label Chrome {
+  [channel=dev] M34 = 0.1
+};
+
+interface PPB_AudioFrame {
+  /**
+   * Determines if a resource is an AudioFrame resource.
+   *
+   * @param[in] resource The <code>PP_Resource</code> to test.
+   *
+   * @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
+   * resource is an AudioFrame resource or <code>PP_FALSE</code> otherwise.
+   */
+  PP_Bool IsAudioFrame([in] PP_Resource resource);
+
+  /**
+   * Gets the timestamp of the audio frame.
+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   *
+   * @return A <code>PP_TimeDelta</code> containing the timestamp of the audio
+   * frame. Given in seconds since the start of the containing audio stream.
+   */
+  PP_TimeDelta GetTimestamp([in] PP_Resource frame);
+
+  /**
+   * Sets the timestamp of the audio frame. Given in seconds since the
+   * start of the containing audio stream.

[bbudge, 2014/01/09 19:03:22]

I think the first sentence is enough here, since you describe the parameter
below. The second sentence is actually a little ambiguous here.

[Peng, 2014/01/09 19:47:48]

Done.

+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   * @param[in] timestamp A <code>PP_TimeDelta</code> containing the timestamp
+   * of the audio frame. Given in seconds since the start of the containing
+   * audio stream.
+   */
+  void SetTimestamp([in] PP_Resource frame, [in] PP_TimeDelta timestamp);
+
+  /**
+   * Gets the sample size of the audio frame.
+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   *
+   * @return The sample size of the audio frame. It always returns 2 (16 bits)

[yzshen1, 2014/01/09 19:27:45]

nit: maybe we don't have to have the last sentence. In that way, we don't have
to update our API version when we decide to return a number other than 2. 

[Peng, 2014/01/09 19:47:48]

Done.

+   * right now.
+   */
+  uint32_t GetSampleSize([in] PP_Resource frame);
+  
+  /**
+   * Gets the number of channels in the audio frame.
+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   *
+   * @return The number of channels in the audio frame.
+   */
+  uint32_t GetNumberOfChannels([in] PP_Resource frame);
+
+  /**
+   * Gets the number of samples in the audio frame.
+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   *
+   * @return The number of samples in the audio frame.
+   * For example, at a sampling rate of 44,100 Hz in stereo audio, a frame
+   * containing 4410 * 2 samples would have a duration of 100 millisecond.

[bbudge, 2014/01/09 19:03:22]

s/millisecond/milliseconds

[Peng, 2014/01/09 19:47:48]

Done.

[Peng, 2014/01/09 19:47:48]

Done.

+   */
+  uint32_t GetNumberOfSamples([in] PP_Resource frame);
+
+  /**
+   * Gets the data buffer for audio frame samples.

[bbudge, 2014/01/09 19:03:22]

s/for/containing the

[Peng, 2014/01/09 19:47:48]

Done.

+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   *
+   * @return A pointer to the beginning of the data buffer.
+   */
+  mem_t GetDataBuffer([in] PP_Resource frame);
+
+  /**
+   * Gets the size of the data buffer in bytes.
+   *
+   * @param[in] frame A <code>PP_Resource</code> corresponding to an audio frame
+   * resource.
+   *
+   * @return The size of the data buffer in bytes.
+   */
+  uint32_t GetDataBufferSize([in] PP_Resource frame);
+};