/* 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_MediaStreamVideoTrack</code> interface. Used for
* receiving video frames from a MediaStream video track in the browser.
*/
[generate_thunk]
label Chrome {
[channel=dev] M34 = 0.1,
M35 = 0.1,
[channel=dev] M36 = 1.0
};
/**
* This enumeration contains video track attributes which are used by
* <code>Configure()</code>.
*/
enum PP_MediaStreamVideoTrack_Attrib {
/**
* Attribute list terminator.
*/
PP_MEDIASTREAMVIDEOTRACK_ATTRIB_NONE = 0,
/**
* The maximum number of frames to hold in the input buffer.
* Note: this is only used as advisory; the browser may allocate more or fewer
* based on available resources. How many frames to buffer depends on usage -
* request at least 2 to make sure latency doesn't cause lost frames. If
* the plugin expects to hold on to more than one frame at a time (e.g. to do
* multi-frame processing), it should request that many more.
* If this attribute is not specified or value 0 is specified for this
* attribute, the default value will be used.
*/
PP_MEDIASTREAMVIDEOTRACK_ATTRIB_BUFFERED_FRAMES = 1,
/**
* The width of video frames in pixels. It should be a multiple of 4.
* If the specified size is different from the video source (webcam),
* frames will be scaled to specified size.
* If this attribute is not specified or value 0 is specified, the original
* frame size of the video track will be used.
*
* Maximum value: 4096 (4K resolution).
*/
PP_MEDIASTREAMVIDEOTRACK_ATTRIB_WIDTH = 2,
/**
* The height of video frames in pixels. It should be a multiple of 4.
* If the specified size is different from the video source (webcam),
* frames will be scaled to specified size.
* If this attribute is not specified or value 0 is specified, the original
* frame size of the video track will be used.
*
* Maximum value: 4096 (4K resolution).
*/
PP_MEDIASTREAMVIDEOTRACK_ATTRIB_HEIGHT = 3,
/**
* The format of video frames. The attribute value is
* a <code>PP_VideoFrame_Format</code>. If the specified format is different
* from the video source (webcam), frames will be converted to specified
* format.
* If this attribute is not specified or value
* <code>PP_VIDEOFRAME_FORMAT_UNKNOWN</code> is specified, the orignal frame
* format of the video track will be used.
*/
PP_MEDIASTREAMVIDEOTRACK_ATTRIB_FORMAT = 4
};
[version=0.1]
interface PPB_MediaStreamVideoTrack {
/**
* Creates a PPB_MediaStreamVideoTrack resource for video output. Call this
* when you will be creating frames and putting them to the track.
*
* @param[in] instance A <code>PP_Instance</code> identifying one instance of
* a module.
*
* @return A <code>PP_Resource</code> corresponding to a
* PPB_MediaStreamVideoTrack resource if successful, 0 if failed.
*/
[version=1.0]
PP_Resource Create([in] PP_Instance instance);
/**
* Determines if a resource is a MediaStream video 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 video track resource or <code>PP_FALSE</code>
* otherwise.
*/
PP_Bool IsMediaStreamVideoTrack([in] PP_Resource resource);
/**
* Configures underlying frame buffers for incoming frames.
* If the application doesn't want to drop frames, then the
* <code>PP_MEDIASTREAMVIDEOTRACK_ATTRIB_BUFFERED_FRAMES</code> should be
* chosen such that inter-frame processing time variability won't overrun the
* input buffer. If the buffer is overfilled, then frames will be dropped.
* The application can detect this by examining the timestamp on returned
* frames. If some attributes are not specified, default values will be used
* for those unspecified attributes. If <code>Configure()</code> is not
* called, default settings will be used.
* Example usage from plugin code:
* @code
* int32_t attribs[] = {
* PP_MEDIASTREAMVIDEOTRACK_ATTRIB_BUFFERED_FRAMES, 4,
* PP_MEDIASTREAMVIDEOTRACK_ATTRIB_NONE};
* track_if->Configure(track, attribs, callback);
* @endcode
*
* @param[in] video_track A <code>PP_Resource</code> corresponding to a video
* 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_MEDIASTREAMVIDEOTRACK_ATTRIB_NONE</code>.
* @param[in] callback <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>.
* Returns <code>PP_ERROR_INPROGRESS</code> if there is a pending call of
* <code>Configure()</code> or <code>GetFrame()</code>, or the plugin
* holds some frames which are not recycled with <code>RecycleFrame()</code>.
* If an error is returned, all attributes and the underlying buffer will not
* be changed.
*/
int32_t Configure([in] PP_Resource video_track,
[in] int32_t[] attrib_list,
[in] PP_CompletionCallback callback);
/**
* Gets attribute value for a given attribute name.
*
* @param[in] video_track A <code>PP_Resource</code> corresponding to a video
* resource.
* @param[in] attrib A <code>PP_MediaStreamVideoTrack_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 video_track,
[in] PP_MediaStreamVideoTrack_Attrib attrib,
[out] int32_t value);
/**
* Returns the track ID of the underlying MediaStream video track.
*
* @param[in] video_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 video_track);
/**
* Checks whether the underlying MediaStream track has ended.
* Calls to GetFrame while the track has ended are safe to make and will
* complete, but will fail.
*
* @param[in] video_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 video_track);
/**
* Gets the next video frame from the MediaStream track.
* If internal processing is slower than the incoming frame rate, new frames
* will be dropped from the incoming stream. Once the input buffer is full,
* frames will be dropped until <code>RecycleFrame()</code> is called to free
* a spot for another frame to be buffered.
* If there are no frames in the input buffer,
* <code>PP_OK_COMPLETIONPENDING</code> will be returned immediately and the
* <code>callback</code> will be called when a new frame is received or an
* error happens.
*
* @param[in] video_track A <code>PP_Resource</code> corresponding to a video
* resource.
* @param[out] frame A <code>PP_Resource</code> corresponding to a VideoFrame
* resource.
* @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
* completion of GetFrame().
*
* @return An int32_t containing a result code from <code>pp_errors.h</code>.
* Returns PP_ERROR_NOMEMORY if <code>max_buffered_frames</code> frames buffer
* was not allocated successfully.
*/
int32_t GetFrame([in] PP_Resource video_track,
[out] PP_Resource frame,
[in] PP_CompletionCallback callback);
/**
* Recycles a frame returned by <code>GetFrame()</code>, so the track can
* reuse the underlying buffer of this frame. And the frame will become
* invalid. The caller should release all references it holds to
* <code>frame</code> and not use it anymore.
*
* @param[in] video_track A <code>PP_Resource</code> corresponding to a video
* resource.
* @param[in] frame A <code>PP_Resource</code> corresponding to a VideoFrame
* resource returned by <code>GetFrame()</code>.
*
* @return An int32_t containing a result code from <code>pp_errors.h</code>.
*/
int32_t RecycleFrame([in] PP_Resource video_track,
[in] PP_Resource frame);
/**
* Closes the MediaStream video track and disconnects it from video source.
* After calling <code>Close()</code>, no new frames will be received.
*
* @param[in] video_track A <code>PP_Resource</code> corresponding to a
* MediaStream video track resource.
*/
void Close([in] PP_Resource video_track);
/**
* Gets a free frame for output. The frame is allocated by
* <code>Configure()</code>. The caller should fill it with frame data, and
* then use |PutFrame()| to send the frame back.
*/
[version=1.0]
int32_t GetEmptyFrame([in] PP_Resource video_track,
[out] PP_Resource frame,
[in] PP_CompletionCallback callback);
/**
* Sends a frame returned by |GetEmptyFrame()| to the output track.
* After this function, the |frame| should not be used anymore and the
* caller should release the reference that it holds.
*/
[version=1.0]
int32_t PutFrame([in] PP_Resource video_track, [in] PP_Resource frame);
};
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