Pepper: Define PPB_VideoEncoder API + Implementation

ppapi/api/ppb_video_encoder.idl

+/* Copyright (c) 2015 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.
+ */
+
+/**
+ * This file defines the <code>PPB_VideoEncoder</code> interface.
+ */
+
+[generate_thunk]
+
+label Chrome {
+  [channel=dev] M42 = 0.1
+};
+
+/**
+ * Video encoder interface.
+ * This interface is still in development (Dev API status) and may change,
+ * so is only supported on Dev channel and Canary currently.
+ *
+ * Typical usage:
+ * - Call Create() to create a new video encoder resource.
+ * - Call GetSupportedFormats() to determine which codecs and profiles are
+ *   available.
+ * - Call Initialize() to initialize the encoder for a supported profile.
+ * - Call GetVideoFrame() to get a blank frame and fill it in, or get a video
+ *   frame from another resource, e.g. <code>PPB_MediaStreamVideoTrack</code>.
+ * - Call Encode() to push the video frame to the encoder. If an external frame
+ *   is pushed, wait for completion to recycle the frame.
+ * - Call GetBitstreamBuffer() continuously (waiting for each previous call to
+ *   complete) to pull encoded pictures from the encoder.
+ * - Call RecycleBitstreamBuffer() after consuming the data in the bitstream
+ *   buffer.
+ * - To destroy the encoder, the plugin should release all of its references to
+ *   it. Any pending callbacks will abort before the encoder is destroyed.
+ *
+ * Available video codecs vary by platform.
+ * All: theora, vorbis, vp8.
+ * Chrome and ChromeOS: h264.
+ * ChromeOS: mpeg4.
+ */
+interface PPB_VideoEncoder {
+  /**
+   * Creates a new video encoder resource.
+   *
+   * @param[in] instance A <code>PP_Instance</code> identifying the instance
+   * with the video encoder.
+   *
+   * @return A <code>PP_Resource</code> corresponding to a video encoder if
+   * successful or 0 otherwise.
+   */
+  PP_Resource Create(
+      [in] PP_Instance instance);
+
+  /**
+   * Determines if the given resource is a video encoder.
+   *
+   * @param[in] resource A <code>PP_Resource</code> identifying a resource.
+   *
+   * @return <code>PP_TRUE</code> if the resource is a
+   * <code>PPB_VideoEncoder</code>, <code>PP_FALSE</code> if the resource is
+   * invalid or some other type.
+   */
+  PP_Bool IsVideoEncoder(
+      [in] PP_Resource resource);
+
+  /**
+   * Gets an array of supported video encoder profiles.
+   * These can be used to choose a profile before calling Initialize().
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[in] output A <code>PP_ArrayOutput</code> to hold the supported
+   * <code>PP_SupportedVideoProfile</code> structs.
+   * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
+   * completion.
+   *
+   * @return If >= 0, the number of supported profiles returned, otherwise an
+   * error code from <code>pp_errors.h</code>.
+   */
+  int32_t GetSupportedProfiles(
+      [in] PP_Resource video_encoder,
+      [in] PP_ArrayOutput output,
+      [in] PP_CompletionCallback callback);
+
+  /**
+   * Initializes a video encoder resource. The plugin should call Initialize()
+   * successfully before calling any of the functions below.
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[in] input_format The <code>PP_VideoFrame_Format</code> of the
+   * frames which will be encoded.
+   * @param[in] input_visible_size A <code>PP_Size</code> specifying the
+   * dimensions of the visible part of the input frames.
+   * @param[in] output_profile A <code>PP_VideoProfile</code> specifying the
+   * codec profile of the encoded output stream.
+   * @param[in] acceleration A <code>PP_HardwareAcceleration</code> specifying
+   * whether to use a hardware accelerated or a software implementation.
+   * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
+   * completion.
+   *
+   * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_NOTSUPPORTED if video encoding is not available, or the
+   * requested codec profile is not supported.
+   */
+  int32_t Initialize(
+      [in] PP_Resource video_encoder,
+      [in] PP_VideoFrame_Format input_format,
+      [in] PP_Size input_visible_size,
+      [in] PP_VideoProfile output_profile,
+      [in] uint32_t initial_bitrate,
+      [in] PP_HardwareAcceleration acceleration,
+      [in] PP_CompletionCallback callback);
+
+  /**
+   * Gets the number of input video frames that the encoder may hold while
+   * encoding. If the plugin is providing the video frames, it should have at
+   * least this many available.
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @return An int32_t containing the number of frames required, or an error
+   * code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
+   */
+  int32_t GetFramesRequired(
+      [in] PP_Resource video_encoder);
+
+  /**
+   * Gets the coded size of the video frames required by the encoder. Coded
+   * size is the logical size of the input frames, in pixels.  The encoder may
+   * have hardware alignment requirements that make this different from
+   * |input_visible_size|, as requested in the call to Initialize().
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[in] coded_size A <code>PP_Size</code> to hold the coded size.
+   * @return An int32_t containing a result code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
+   */
+  int32_t GetFrameCodedSize(
+      [in] PP_Resource video_encoder,
+      [out] PP_Size coded_size);
+
+  /**
+   * Gets a blank video frame which can be filled with video data and passed
+   * to the encoder.
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[out] video_frame A blank <code>PPB_VideoFrame</code> resource.
+   * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
+   * completion.
+   *
+   * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
+   */
+  int32_t GetVideoFrame(
+      [in] PP_Resource video_encoder,
+      [out] PP_Resource video_frame,
+      [in] PP_CompletionCallback callback);
+
+  /**
+   * Encodes a video frame.
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[in] video_frame The <code>PPB_VideoFrame</code> to be encoded.
+   * @param[in] force_keyframe A <code>PP_Bool> specifying whether the encoder
+   * should emit a key frame for this video frame.
+   * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
+   * completion. Plugins that pass <code>PPB_VideoFrame</code> resources owned
+   * by other resources should wait for completion before reusing them.
+   *
+   * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
+   */
+  int32_t Encode(
+      [in] PP_Resource video_encoder,
+      [in] PP_Resource video_frame,
+      [in] PP_Bool force_keyframe,
+      [in] PP_CompletionCallback callback);
+
+  /**
+   * Gets the next encoded bitstream buffer from the encoder.
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[out] bitstream_buffer A <code>PP_BitstreamBuffer</code> containing
+   * encoded video data.
+   * @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
+   * completion. The plugin can call GetBitstreamBuffer from the callback in
+   * order to continuously "pull" bitstream buffers from the encoder.
+   *
+   * @return An int32_t containing an error code from <code>pp_errors.h</code>.
+   * Returns PP_ERROR_FAILED if Initialize() has not successfully completed.
+   * Returns PP_ERROR_INPROGRESS if a prior call to GetBitstreamBuffer() has
+   * not completed.
+   */
+  int32_t GetBitstreamBuffer(
+      [in] PP_Resource video_encoder,
+      [out] PP_BitstreamBuffer bitstream_buffer,
+      [in] PP_CompletionCallback callback);
+
+  /**
+   * Recycles a bitstream buffer back to the encoder.
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[in] bitstream_buffer A <code>PP_BitstreamBuffer</code> that is no
+   * longer needed by the plugin.
+   */
+  void RecycleBitstreamBuffer(
+      [in] PP_Resource video_encoder,
+      [in] PP_BitstreamBuffer bitstream_buffer);
+
+  /**
+   * Requests a change to encoding parameters. This is only a request,
+   * fulfilled on a best-effort basis.
+   *
+   * @param[in] video_encoder A <code>PP_Resource</code> identifying the video
+   * encoder.
+   * @param[in] bitrate The requested new bitrate, in bits per second.
+   * @param[in] framerate The requested new framerate, in frames per second.
+   */
+  void RequestEncodingParametersChange(
+      [in] PP_Resource video_encoder,
+      [in] uint32_t bitrate,
+      [in] uint32_t framerate);
+};