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/* Copyright 2014 The Chromium Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/**
* Defines the <code>PPB_MediaStreamAudioTrack</code> interface. Used for
* receiving audio samples from a MediaStream audio track in the browser.
*/
[generate_thunk]
label Chrome {
[channel=dev] M34 = 0.1,
M35 = 0.1
};
/**
* This enumeration contains audio track attributes which are used by
* <code>Configure()</code>.
*/
enum PP_MediaStreamAudioTrack_Attrib {
/**
* Attribute list terminator.
*/
PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE = 0,
/**
* The maximum number of buffers to hold audio samples.
* Note: this is only used as advisory; the browser may allocate more or fewer
* based on available resources. How many buffers depends on usage -
* request at least 2 to make sure latency doesn't cause lost samples. If
* the plugin expects to hold on to more than one buffer at a time (e.g. to do
* multi-buffer processing), it should request that many more.
*/
PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS = 1,
/**
* The sample rate of audio data in buffers. The attribute value is a
* <code>PP_AudioBuffer_SampleRate</code>.
*/
PP_MEDIASTREAMAUDIOTRACK_ATTRIB_SAMPLE_RATE = 2,
/**
* The sample size of audio data in buffers in bytes. The attribute value is a
* <code>PP_AudioBuffer_SampleSize</code>.
*/
PP_MEDIASTREAMAUDIOTRACK_ATTRIB_SAMPLE_SIZE = 3,
/**
* The number of channels in audio buffers.
*
* Supported values: 1, 2
*/
PP_MEDIASTREAMAUDIOTRACK_ATTRIB_CHANNELS = 4,
/**
* The duration of an audio buffer in milliseconds.
*
* Valid range: 10 to 10000
*/
PP_MEDIASTREAMAUDIOTRACK_ATTRIB_DURATION = 5
};
[version=0.1]
interface PPB_MediaStreamAudioTrack {
/**
* Determines if a resource is a MediaStream audio track 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 a Mediastream audio track resource or <code>PP_FALSE</code>
* otherwise.
*/
PP_Bool IsMediaStreamAudioTrack([in] PP_Resource resource);
/**
* Configures underlying buffers for incoming audio samples.
* If the application doesn't want to drop samples, then the
* <code>PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS</code> should be
* chosen such that inter-buffer processing time variability won't overrun all
* the input buffers. If all buffers are filled, then samples will be
* dropped. The application can detect this by examining the timestamp on
* returned buffers. If <code>Configure()</code> is not called, default
* settings will be used. Calls to Configure while the plugin holds
* buffers will fail.
* Example usage from plugin code:
* @code
* int32_t attribs[] = {
* PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS, 4,
* PP_MEDIASTREAMAUDIOTRACK_ATTRIB_DURATION, 10,
* PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE};
* track_if->Configure(track, attribs, callback);
* @endcode
*
* @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
* resource.
* @param[in] attrib_list A list of attribute name-value pairs in which each
* attribute is immediately followed by the corresponding desired value.
* The list is terminated by
* <code>PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE</code>.
* @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
* completion of <code>Configure()</code>.
*
* @return An int32_t containing a result code from <code>pp_errors.h</code>.
*/
int32_t Configure([in] PP_Resource audio_track,
[in] int32_t[] attrib_list,
[in] PP_CompletionCallback callback);
/**
* Gets attribute value for a given attribute name.
*
* @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
* resource.
* @param[in] attrib A <code>PP_MediaStreamAudioTrack_Attrib</code> for
* querying.
* @param[out] value A int32_t for storing the attribute value on success.
* Otherwise, the value will not be changed.
*
* @return An int32_t containing a result code from <code>pp_errors.h</code>.
*/
int32_t GetAttrib([in] PP_Resource audio_track,
[in] PP_MediaStreamAudioTrack_Attrib attrib,
[out] int32_t value);
/**
* Returns the track ID of the underlying MediaStream audio track.
*
* @param[in] audio_track The <code>PP_Resource</code> to check.
*
* @return A <code>PP_Var</code> containing the MediaStream track ID as
* a string.
*/
PP_Var GetId([in] PP_Resource audio_track);
/**
* Checks whether the underlying MediaStream track has ended.
* Calls to GetBuffer while the track has ended are safe to make and will
* complete, but will fail.
*
* @param[in] audio_track The <code>PP_Resource</code> to check.
*
* @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
* MediaStream track has ended or <code>PP_FALSE</code> otherwise.
*/
[on_failure=PP_TRUE]
PP_Bool HasEnded([in] PP_Resource audio_track);
/**
* Gets the next audio buffer from the MediaStream track.
* If internal processing is slower than the incoming buffer rate, new buffers
* will be dropped from the incoming stream. Once all buffers are full,
* audio samples will be dropped until <code>RecycleBuffer()</code> is called
* to free a slot for another buffer.
* If there are no audio data in the input buffer,
* <code>PP_OK_COMPLETIONPENDING</code> will be returned immediately and the
* <code>callback</code> will be called, when a new buffer of audio samples
* is received or an error happens.
*
* @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
* resource.
* @param[out] buffer A <code>PP_Resource</code> corresponding to
* an AudioBuffer resource.
* @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
* completion of GetBuffer().
*
* @return An int32_t containing a result code from <code>pp_errors.h</code>.
*/
int32_t GetBuffer([in] PP_Resource audio_track,
[out] PP_Resource buffer,
[in] PP_CompletionCallback callback);
/**
* Recycles a buffer returned by <code>GetBuffer()</code>, so the track can
* reuse the buffer. And the buffer will become invalid. The caller should
* release all references it holds to <code>buffer</code> and not use it
* anymore.
*
* @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
* resource.
* @param[in] buffer A <code>PP_Resource</code> corresponding to
* an AudioBuffer resource returned by <code>GetBuffer()</code>.
*
* @return An int32_t containing a result code from <code>pp_errors.h</code>.
*/
int32_t RecycleBuffer([in] PP_Resource audio_track,
[in] PP_Resource buffer);
/**
* Closes the MediaStream audio track and disconnects it from the audio
* source. After calling <code>Close()</code>, no new buffers will be
* received.
*
* @param[in] audio_track A <code>PP_Resource</code> corresponding to a
* MediaStream audio track resource.
*/
void Close([in] PP_Resource audio_track);
};
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