ppapi/c/ppb_media_stream_audio_track.h

   1 /* Copyright 2014 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
   6 /* From ppb_media_stream_audio_track.idl modified Fri Mar 28 10:13:34 2014. */
   7
   8 #ifndef PPAPI_C_PPB_MEDIA_STREAM_AUDIO_TRACK_H_
   9 #define PPAPI_C_PPB_MEDIA_STREAM_AUDIO_TRACK_H_
  10
  11 #include "ppapi/c/pp_bool.h"
  12 #include "ppapi/c/pp_completion_callback.h"
  13 #include "ppapi/c/pp_macros.h"
  14 #include "ppapi/c/pp_resource.h"
  15 #include "ppapi/c/pp_stdint.h"
  16 #include "ppapi/c/pp_var.h"
  17
  18 #define PPB_MEDIASTREAMAUDIOTRACK_INTERFACE_0_1 "PPB_MediaStreamAudioTrack;0.1"
  19 #define PPB_MEDIASTREAMAUDIOTRACK_INTERFACE \
  20     PPB_MEDIASTREAMAUDIOTRACK_INTERFACE_0_1
  21
  22 /**
  23  * @file
  24  * Defines the <code>PPB_MediaStreamAudioTrack</code> interface. Used for
  25  * receiving audio samples from a MediaStream audio track in the browser.
  26  */
  27
  28
  29 /**
  30  * @addtogroup Enums
  31  * @{
  32  */
  33 /**
  34  * This enumeration contains audio track attributes which are used by
  35  * <code>Configure()</code>.
  36  */
  37 typedef enum {
  38   /**
  39    * Attribute list terminator.
  40    */
  41   PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE = 0,
  42   /**
  43    * The maximum number of buffers to hold audio samples.
  44    * Note: this is only used as advisory; the browser may allocate more or fewer
  45    * based on available resources. How many buffers depends on usage -
  46    * request at least 2 to make sure latency doesn't cause lost samples. If
  47    * the plugin expects to hold on to more than one buffer at a time (e.g. to do
  48    * multi-buffer processing), it should request that many more.
  49    */
  50   PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS = 1,
  51   /**
  52    * The sample rate of audio data in buffers. The attribute value is a
  53    * <code>PP_AudioBuffer_SampleRate</code>.
  54    */
  55   PP_MEDIASTREAMAUDIOTRACK_ATTRIB_SAMPLE_RATE = 2,
  56   /**
  57    * The sample size of audio data in buffers in bytes. The attribute value is a
  58    * <code>PP_AudioBuffer_SampleSize</code>.
  59    */
  60   PP_MEDIASTREAMAUDIOTRACK_ATTRIB_SAMPLE_SIZE = 3,
  61   /**
  62    * The number of channels in audio buffers.
  63    *
  64    * Supported values: 1, 2
  65    */
  66   PP_MEDIASTREAMAUDIOTRACK_ATTRIB_CHANNELS = 4,
  67   /**
  68    * The duration of an audio buffer in milliseconds.
  69    *
  70    * Valid range: 10 to 10000
  71    */
  72   PP_MEDIASTREAMAUDIOTRACK_ATTRIB_DURATION = 5
  73 } PP_MediaStreamAudioTrack_Attrib;
  74 /**
  75  * @}
  76  */
  77
  78 /**
  79  * @addtogroup Interfaces
  80  * @{
  81  */
  82 struct PPB_MediaStreamAudioTrack_0_1 {
  83   /**
  84    * Determines if a resource is a MediaStream audio track resource.
  85    *
  86    * @param[in] resource The <code>PP_Resource</code> to test.
  87    *
  88    * @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
  89    * resource is a Mediastream audio track resource or <code>PP_FALSE</code>
  90    * otherwise.
  91    */
  92   PP_Bool (*IsMediaStreamAudioTrack)(PP_Resource resource);
  93   /**
  94    * Configures underlying buffers for incoming audio samples.
  95    * If the application doesn't want to drop samples, then the
  96    * <code>PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS</code> should be
  97    * chosen such that inter-buffer processing time variability won't overrun all
  98    * the input buffers. If all buffers are filled, then samples will be
  99    * dropped. The application can detect this by examining the timestamp on
 100    * returned buffers. If <code>Configure()</code> is not called, default
 101    * settings will be used.
 102    * Example usage from plugin code:
 103    * @code
 104    * int32_t attribs[] = {
 105    *     PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS, 4,
 106    *     PP_MEDIASTREAMAUDIOTRACK_ATTRIB_DURATION, 10,
 107    *     PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE};
 108    * track_if->Configure(track, attribs, callback);
 109    * @endcode
 110    *
 111    * @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
 112    * resource.
 113    * @param[in] attrib_list A list of attribute name-value pairs in which each
 114    * attribute is immediately followed by the corresponding desired value.
 115    * The list is terminated by
 116    * <code>PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE</code>.
 117    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
 118    * completion of <code>Configure()</code>.
 119    *
 120    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 121    */
 122   int32_t (*Configure)(PP_Resource audio_track,
 123                        const int32_t attrib_list[],
 124                        struct PP_CompletionCallback callback);
 125   /**
 126    * Gets attribute value for a given attribute name.
 127    *
 128    * @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
 129    * resource.
 130    * @param[in] attrib A <code>PP_MediaStreamAudioTrack_Attrib</code> for
 131    * querying.
 132    * @param[out] value A int32_t for storing the attribute value on success.
 133    * Otherwise, the value will not be changed.
 134    *
 135    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 136    */
 137   int32_t (*GetAttrib)(PP_Resource audio_track,
 138                        PP_MediaStreamAudioTrack_Attrib attrib,
 139                        int32_t* value);
 140   /**
 141    * Returns the track ID of the underlying MediaStream audio track.
 142    *
 143    * @param[in] audio_track The <code>PP_Resource</code> to check.
 144    *
 145    * @return A <code>PP_Var</code> containing the MediaStream track ID as
 146    * a string.
 147    */
 148   struct PP_Var (*GetId)(PP_Resource audio_track);
 149   /**
 150    * Checks whether the underlying MediaStream track has ended.
 151    * Calls to GetBuffer while the track has ended are safe to make and will
 152    * complete, but will fail.
 153    *
 154    * @param[in] audio_track The <code>PP_Resource</code> to check.
 155    *
 156    * @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
 157    * MediaStream track has ended or <code>PP_FALSE</code> otherwise.
 158    */
 159   PP_Bool (*HasEnded)(PP_Resource audio_track);
 160   /**
 161    * Gets the next audio buffer from the MediaStream track.
 162    * If internal processing is slower than the incoming buffer rate, new buffers
 163    * will be dropped from the incoming stream. Once all buffers are full,
 164    * audio samples will be dropped until <code>RecycleBuffer()</code> is called
 165    * to free a slot for another buffer.
 166    * If there are no audio data in the input buffer,
 167    * <code>PP_OK_COMPLETIONPENDING</code> will be returned immediately and the
 168    * <code>callback</code> will be called, when a new buffer of audio samples
 169    * is received or an error happens.
 170    *
 171    * @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
 172    * resource.
 173    * @param[out] buffer A <code>PP_Resource</code> corresponding to
 174    * an AudioBuffer resource.
 175    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
 176    * completion of GetBuffer().
 177    *
 178    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 179    */
 180   int32_t (*GetBuffer)(PP_Resource audio_track,
 181                        PP_Resource* buffer,
 182                        struct PP_CompletionCallback callback);
 183   /**
 184    * Recycles a buffer returned by <code>GetBuffer()</code>, so the track can
 185    * reuse the buffer. And the buffer will become invalid. The caller should
 186    * release all references it holds to <code>buffer</code> and not use it
 187    * anymore.
 188    *
 189    * @param[in] audio_track A <code>PP_Resource</code> corresponding to an audio
 190    * resource.
 191    * @param[in] buffer A <code>PP_Resource</code> corresponding to
 192    * an AudioBuffer resource returned by <code>GetBuffer()</code>.
 193    *
 194    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 195    */
 196   int32_t (*RecycleBuffer)(PP_Resource audio_track, PP_Resource buffer);
 197   /**
 198    * Closes the MediaStream audio track and disconnects it from the audio
 199    * source. After calling <code>Close()</code>, no new buffers will be
 200    * received.
 201    *
 202    * @param[in] audio_track A <code>PP_Resource</code> corresponding to a
 203    * MediaStream audio track resource.
 204    */
 205   void (*Close)(PP_Resource audio_track);
 206 };
 207
 208 typedef struct PPB_MediaStreamAudioTrack_0_1 PPB_MediaStreamAudioTrack;
 209 /**
 210  * @}
 211  */
 212
 213 #endif  /* PPAPI_C_PPB_MEDIA_STREAM_AUDIO_TRACK_H_ */
 214