ppapi/c/ppb_media_stream_video_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_video_track.idl modified Mon Apr  7 15:25:56 2014. */
   7
   8 #ifndef PPAPI_C_PPB_MEDIA_STREAM_VIDEO_TRACK_H_
   9 #define PPAPI_C_PPB_MEDIA_STREAM_VIDEO_TRACK_H_
  10
  11 #include "ppapi/c/pp_bool.h"
  12 #include "ppapi/c/pp_completion_callback.h"
  13 #include "ppapi/c/pp_instance.h"
  14 #include "ppapi/c/pp_macros.h"
  15 #include "ppapi/c/pp_resource.h"
  16 #include "ppapi/c/pp_stdint.h"
  17 #include "ppapi/c/pp_var.h"
  18
  19 #define PPB_MEDIASTREAMVIDEOTRACK_INTERFACE_0_1 "PPB_MediaStreamVideoTrack;0.1"
  20 #define PPB_MEDIASTREAMVIDEOTRACK_INTERFACE_1_0 \
  21     "PPB_MediaStreamVideoTrack;1.0" /* dev */
  22 #define PPB_MEDIASTREAMVIDEOTRACK_INTERFACE \
  23     PPB_MEDIASTREAMVIDEOTRACK_INTERFACE_0_1
  24
  25 /**
  26  * @file
  27  * Defines the <code>PPB_MediaStreamVideoTrack</code> interface. Used for
  28  * receiving video frames from a MediaStream video track in the browser.
  29  */
  30
  31
  32 /**
  33  * @addtogroup Enums
  34  * @{
  35  */
  36 /**
  37  * This enumeration contains video track attributes which are used by
  38  * <code>Configure()</code>.
  39  */
  40 typedef enum {
  41   /**
  42    * Attribute list terminator.
  43    */
  44   PP_MEDIASTREAMVIDEOTRACK_ATTRIB_NONE = 0,
  45   /**
  46    * The maximum number of frames to hold in the input buffer.
  47    * Note: this is only used as advisory; the browser may allocate more or fewer
  48    * based on available resources. How many frames to buffer depends on usage -
  49    * request at least 2 to make sure latency doesn't cause lost frames. If
  50    * the plugin expects to hold on to more than one frame at a time (e.g. to do
  51    * multi-frame processing), it should request that many more.
  52    * If this attribute is not specified or value 0 is specified for this
  53    * attribute, the default value will be used.
  54    */
  55   PP_MEDIASTREAMVIDEOTRACK_ATTRIB_BUFFERED_FRAMES = 1,
  56   /**
  57    * The width of video frames in pixels. It should be a multiple of 4.
  58    * If the specified size is different from the video source (webcam),
  59    * frames will be scaled to specified size.
  60    * If this attribute is not specified or value 0 is specified, the original
  61    * frame size of the video track will be used.
  62    *
  63    * Maximum value: 4096 (4K resolution).
  64    */
  65   PP_MEDIASTREAMVIDEOTRACK_ATTRIB_WIDTH = 2,
  66   /**
  67    * The height of video frames in pixels. It should be a multiple of 4.
  68    * If the specified size is different from the video source (webcam),
  69    * frames will be scaled to specified size.
  70    * If this attribute is not specified or value 0 is specified, the original
  71    * frame size of the video track will be used.
  72    *
  73    * Maximum value: 4096 (4K resolution).
  74    */
  75   PP_MEDIASTREAMVIDEOTRACK_ATTRIB_HEIGHT = 3,
  76   /**
  77    * The format of video frames. The attribute value is
  78    * a <code>PP_VideoFrame_Format</code>. If the specified format is different
  79    * from the video source (webcam), frames will be converted to specified
  80    * format.
  81    * If this attribute is not specified or value
  82    * <code>PP_VIDEOFRAME_FORMAT_UNKNOWN</code> is specified, the orignal frame
  83    * format of the video track will be used.
  84    */
  85   PP_MEDIASTREAMVIDEOTRACK_ATTRIB_FORMAT = 4
  86 } PP_MediaStreamVideoTrack_Attrib;
  87 /**
  88  * @}
  89  */
  90
  91 /**
  92  * @addtogroup Interfaces
  93  * @{
  94  */
  95 struct PPB_MediaStreamVideoTrack_1_0 { /* dev */
  96   /**
  97    * Creates a PPB_MediaStreamVideoTrack resource for video output. Call this
  98    * when you will be creating frames and putting them to the track.
  99    *
 100    * @param[in] instance A <code>PP_Instance</code> identifying one instance of
 101    * a module.
 102    *
 103    * @return A <code>PP_Resource</code> corresponding to a
 104    * PPB_MediaStreamVideoTrack resource if successful, 0 if failed.
 105    */
 106   PP_Resource (*Create)(PP_Instance instance);
 107   /**
 108    * Determines if a resource is a MediaStream video track resource.
 109    *
 110    * @param[in] resource The <code>PP_Resource</code> to test.
 111    *
 112    * @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
 113    * resource is a Mediastream video track resource or <code>PP_FALSE</code>
 114    * otherwise.
 115    */
 116   PP_Bool (*IsMediaStreamVideoTrack)(PP_Resource resource);
 117   /**
 118    * Configures underlying frame buffers for incoming frames.
 119    * If the application doesn't want to drop frames, then the
 120    * <code>PP_MEDIASTREAMVIDEOTRACK_ATTRIB_BUFFERED_FRAMES</code> should be
 121    * chosen such that inter-frame processing time variability won't overrun the
 122    * input buffer. If the buffer is overfilled, then frames will be dropped.
 123    * The application can detect this by examining the timestamp on returned
 124    * frames. If some attributes are not specified, default values will be used
 125    * for those unspecified attributes. If <code>Configure()</code> is not
 126    * called, default settings will be used.
 127    * Example usage from plugin code:
 128    * @code
 129    * int32_t attribs[] = {
 130    *     PP_MEDIASTREAMVIDEOTRACK_ATTRIB_BUFFERED_FRAMES, 4,
 131    *     PP_MEDIASTREAMVIDEOTRACK_ATTRIB_NONE};
 132    * track_if->Configure(track, attribs, callback);
 133    * @endcode
 134    *
 135    * @param[in] video_track A <code>PP_Resource</code> corresponding to a video
 136    * resource.
 137    * @param[in] attrib_list A list of attribute name-value pairs in which each
 138    * attribute is immediately followed by the corresponding desired value.
 139    * The list is terminated by
 140    * <code>PP_MEDIASTREAMVIDEOTRACK_ATTRIB_NONE</code>.
 141    * @param[in] callback <code>PP_CompletionCallback</code> to be called upon
 142    * completion of <code>Configure()</code>.
 143    *
 144    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 145    * Returns <code>PP_ERROR_INPROGRESS</code> if there is a pending call of
 146    * <code>Configure()</code> or <code>GetFrame()</code>, or the plugin
 147    * holds some frames which are not recycled with <code>RecycleFrame()</code>.
 148    * If an error is returned, all attributes and the underlying buffer will not
 149    * be changed.
 150    */
 151   int32_t (*Configure)(PP_Resource video_track,
 152                        const int32_t attrib_list[],
 153                        struct PP_CompletionCallback callback);
 154   /**
 155    * Gets attribute value for a given attribute name.
 156    *
 157    * @param[in] video_track A <code>PP_Resource</code> corresponding to a video
 158    * resource.
 159    * @param[in] attrib A <code>PP_MediaStreamVideoTrack_Attrib</code> for
 160    * querying.
 161    * @param[out] value A int32_t for storing the attribute value on success.
 162    * Otherwise, the value will not be changed.
 163    *
 164    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 165    */
 166   int32_t (*GetAttrib)(PP_Resource video_track,
 167                        PP_MediaStreamVideoTrack_Attrib attrib,
 168                        int32_t* value);
 169   /**
 170    * Returns the track ID of the underlying MediaStream video track.
 171    *
 172    * @param[in] video_track The <code>PP_Resource</code> to check.
 173    *
 174    * @return A <code>PP_Var</code> containing the MediaStream track ID as
 175    * a string.
 176    */
 177   struct PP_Var (*GetId)(PP_Resource video_track);
 178   /**
 179    * Checks whether the underlying MediaStream track has ended.
 180    * Calls to GetFrame while the track has ended are safe to make and will
 181    * complete, but will fail.
 182    *
 183    * @param[in] video_track The <code>PP_Resource</code> to check.
 184    *
 185    * @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
 186    * MediaStream track has ended or <code>PP_FALSE</code> otherwise.
 187    */
 188   PP_Bool (*HasEnded)(PP_Resource video_track);
 189   /**
 190    * Gets the next video frame from the MediaStream track.
 191    * If internal processing is slower than the incoming frame rate, new frames
 192    * will be dropped from the incoming stream. Once the input buffer is full,
 193    * frames will be dropped until <code>RecycleFrame()</code> is called to free
 194    * a spot for another frame to be buffered.
 195    * If there are no frames in the input buffer,
 196    * <code>PP_OK_COMPLETIONPENDING</code> will be returned immediately and the
 197    * <code>callback</code> will be called when a new frame is received or an
 198    * error happens.
 199    *
 200    * @param[in] video_track A <code>PP_Resource</code> corresponding to a video
 201    * resource.
 202    * @param[out] frame A <code>PP_Resource</code> corresponding to a VideoFrame
 203    * resource.
 204    * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
 205    * completion of GetFrame().
 206    *
 207    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 208    * Returns PP_ERROR_NOMEMORY if <code>max_buffered_frames</code> frames buffer
 209    * was not allocated successfully.
 210    */
 211   int32_t (*GetFrame)(PP_Resource video_track,
 212                       PP_Resource* frame,
 213                       struct PP_CompletionCallback callback);
 214   /**
 215    * Recycles a frame returned by <code>GetFrame()</code>, so the track can
 216    * reuse the underlying buffer of this frame. And the frame will become
 217    * invalid. The caller should release all references it holds to
 218    * <code>frame</code> and not use it anymore.
 219    *
 220    * @param[in] video_track A <code>PP_Resource</code> corresponding to a video
 221    * resource.
 222    * @param[in] frame A <code>PP_Resource</code> corresponding to a VideoFrame
 223    * resource returned by <code>GetFrame()</code>.
 224    *
 225    * @return An int32_t containing a result code from <code>pp_errors.h</code>.
 226    */
 227   int32_t (*RecycleFrame)(PP_Resource video_track, PP_Resource frame);
 228   /**
 229    * Closes the MediaStream video track and disconnects it from video source.
 230    * After calling <code>Close()</code>, no new frames will be received.
 231    *
 232    * @param[in] video_track A <code>PP_Resource</code> corresponding to a
 233    * MediaStream video track resource.
 234    */
 235   void (*Close)(PP_Resource video_track);
 236   /**
 237    * Gets a free frame for output. The frame is allocated by
 238    * <code>Configure()</code>. The caller should fill it with frame data, and
 239    * then use |PutFrame()| to send the frame back.
 240    */
 241   int32_t (*GetEmptyFrame)(PP_Resource video_track,
 242                            PP_Resource* frame,
 243                            struct PP_CompletionCallback callback);
 244   /**
 245    * Sends a frame returned by |GetEmptyFrame()| to the output track.
 246    * After this function, the |frame| should not be used anymore and the
 247    * caller should release the reference that it holds.
 248    */
 249   int32_t (*PutFrame)(PP_Resource video_track, PP_Resource frame);
 250 };
 251
 252 struct PPB_MediaStreamVideoTrack_0_1 {
 253   PP_Bool (*IsMediaStreamVideoTrack)(PP_Resource resource);
 254   int32_t (*Configure)(PP_Resource video_track,
 255                        const int32_t attrib_list[],
 256                        struct PP_CompletionCallback callback);
 257   int32_t (*GetAttrib)(PP_Resource video_track,
 258                        PP_MediaStreamVideoTrack_Attrib attrib,
 259                        int32_t* value);
 260   struct PP_Var (*GetId)(PP_Resource video_track);
 261   PP_Bool (*HasEnded)(PP_Resource video_track);
 262   int32_t (*GetFrame)(PP_Resource video_track,
 263                       PP_Resource* frame,
 264                       struct PP_CompletionCallback callback);
 265   int32_t (*RecycleFrame)(PP_Resource video_track, PP_Resource frame);
 266   void (*Close)(PP_Resource video_track);
 267 };
 268
 269 typedef struct PPB_MediaStreamVideoTrack_0_1 PPB_MediaStreamVideoTrack;
 270 /**
 271  * @}
 272  */
 273
 274 #endif  /* PPAPI_C_PPB_MEDIA_STREAM_VIDEO_TRACK_H_ */
 275