/* 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 PPB_MediaStreamAudioTrack 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 * Configure(). */ 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 * PP_AudioBuffer_SampleRate. */ PP_MEDIASTREAMAUDIOTRACK_ATTRIB_SAMPLE_RATE = 2, /** * The sample size of audio data in buffers in bytes. The attribute value is a * PP_AudioBuffer_SampleSize. */ 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 PP_Resource to test. * * @return A PP_Bool with PP_TRUE if the given * resource is a Mediastream audio track resource or PP_FALSE * 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 * PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS 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 Configure() 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 PP_Resource 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 * PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE. * @param[in] callback A PP_CompletionCallback to be called upon * completion of Configure(). * * @return An int32_t containing a result code from pp_errors.h. */ 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 PP_Resource corresponding to an audio * resource. * @param[in] attrib A PP_MediaStreamAudioTrack_Attrib 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 pp_errors.h. */ 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 PP_Resource to check. * * @return A PP_Var 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 PP_Resource to check. * * @return A PP_Bool with PP_TRUE if the given * MediaStream track has ended or PP_FALSE 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 RecycleBuffer() is called * to free a slot for another buffer. * If there are no audio data in the input buffer, * PP_OK_COMPLETIONPENDING will be returned immediately and the * callback will be called, when a new buffer of audio samples * is received or an error happens. * * @param[in] audio_track A PP_Resource corresponding to an audio * resource. * @param[out] buffer A PP_Resource corresponding to * an AudioBuffer resource. * @param[in] callback A PP_CompletionCallback to be called upon * completion of GetBuffer(). * * @return An int32_t containing a result code from pp_errors.h. */ int32_t GetBuffer([in] PP_Resource audio_track, [out] PP_Resource buffer, [in] PP_CompletionCallback callback); /** * Recycles a buffer returned by GetBuffer(), so the track can * reuse the buffer. And the buffer will become invalid. The caller should * release all references it holds to buffer and not use it * anymore. * * @param[in] audio_track A PP_Resource corresponding to an audio * resource. * @param[in] buffer A PP_Resource corresponding to * an AudioBuffer resource returned by GetBuffer(). * * @return An int32_t containing a result code from pp_errors.h. */ 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 Close(), no new buffers will be * received. * * @param[in] audio_track A PP_Resource corresponding to a * MediaStream audio track resource. */ void Close([in] PP_Resource audio_track); };