Pepper VideoDecoder API definition.

ppapi/cpp/video_decoder.h

+// Copyright (c) 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.
+
+#ifndef PPAPI_CPP_VIDEO_DECODER_H_
+#define PPAPI_CPP_VIDEO_DECODER_H_
+
+#include "ppapi/c/pp_codecs.h"
+#include "ppapi/c/pp_size.h"
+#include "ppapi/cpp/completion_callback.h"
+#include "ppapi/cpp/graphics_3d.h"
+#include "ppapi/cpp/resource.h"
+#include "ppapi/cpp/size.h"
+
+/// @file
+/// This file defines the API to create and use a VideoDecoder resource.
+
+struct PP_FileInfo;
+
+namespace pp {
+
+class InstanceHandle;
+
+/// Video decoder interface.
+///
+/// Typical usage:
+/// - Call Create() to create a new video decoder resource.
+/// - Call Initialize() to initialize it with a 3d graphics context and the
+///   desired codec profile.
+/// - Call Decode() continuously (waiting for each previous call to complete) to
+///   push bitstream buffers to the decoder.
+/// - Call GetPicture() continuously (waiting for each previous call to
+///   complete) to pull decoded pictures from the decoder.
+/// - Call Flush() to signal end of stream to the decoder and perform shutdown
+///   when it completes.
+/// - Call Reset() to quickly stop the decoder (e.g. to implement Seek) and wait
+///   for the callback before restarting decoding at another point.
+/// - To destroy the decoder, the plugin should release all of its references to
+///   it. Any pending callbacks will abort before the decoder is destroyed.
+///
+/// Available video codecs vary by platform.
+/// All: theora, vorbis, vp8.
+/// Chrome and ChromeOS: aac, h264.
+/// ChromeOS: mpeg4.
+class VideoDecoder : public Resource {
+ public:
+  /// Default constructor for creating an is_null() <code>VideoDecoder</code>
+  /// object.
+  VideoDecoder();
+
+  /// A constructor used to create a <code>VideoDecoder</code> and associate it
+  /// with the provided <code>Instance</code>.
+  /// @param[in] instance The instance with which this resource will be
+  /// associated.
+  explicit VideoDecoder(const InstanceHandle& instance);
+
+  /// The copy constructor for <code>VideoDecoder</code>.
+  /// @param[in] other A reference to a <code>VideoDecoder</code>.
+  VideoDecoder(const VideoDecoder& other);
+
+  /// Initializes a video decoder resource. This should be called after Create()
+  /// and before any other functions.
+  ///
+  /// @param[in] video_decoder A <code>PP_Resource</code> identifying the video
+  /// decoder.
+  /// @param[in] profile A <code>PP_VideoProfile</code> specifying the video
+  /// codec profile.
+  /// @param[in] allow_software_fallback A <code>PP_Bool</code> specifying
+  /// whether the decoder can fall back to software decoding if a suitable
+  /// hardware decoder isn't available.
+  /// @param[in] callback A <code>CompletionCallback</code> to be called on
+  /// completion.
+  ///
+  /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  /// Returns PP_ERROR_NOTSUPPORTED if video decoding is not available, or the
+  /// requested profile is not supported. In this case, the client may call
+  /// Initialize() again with different parameters to find a good configuration.
+  int32_t Initialize(const Graphics3D& graphics3d_context,
+                     PP_VideoProfile profile,
+                     bool allow_software_fallback,
+                     const CompletionCallback& callback);
+
+  /// Decodes a bitstream buffer. Copies |size| bytes of data from the plugin's
+  /// |buffer|. The plugin should maintain the buffer and not call Decode()
+  /// again until the decoder signals completion by returning PP_OK or by
+  /// running |callback|.
+  ///
+  /// In general, each bitstream buffer should contain a demuxed bitstream frame
+  /// for the selected video codec. For example, H264 decoders expect to receive
+  /// one AnnexB NAL unit, including the 4 byte start code prefix, while VP8
+  /// decoders expect to receive a bitstream frame without the IVF frame header.
+  ///
+  /// If the call to Decode() eventually results in a picture, the |decode_id|
+  /// parameter is copied into the returned picture. The plugin can use this to
+  /// associate decoded pictures with Decode() calls (e.g. to assign timestamps
+  /// or frame numbers to pictures.) This value is opaque to the API so the
+  /// plugin is free to pass any value.
+  ///
+  /// @param[in] decode_id An optional value, chosen by the plugin, that can be
+  /// used to associate calls to Decode() with decoded pictures returned by
+  /// GetPicture().
+  /// @param[in] size Buffer size in bytes.
+  /// @param[in] buffer Starting address of buffer.
+  /// @param[in] callback A <code>CompletionCallback</code> to be called on
+  /// completion.
+  ///
+  /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  int32_t Decode(uint32_t decode_id,
+                 uint32_t size,
+                 const void* buffer,
+                 const CompletionCallback& callback);
+
+  /// Gets the next picture from the decoder. The picture is valid after the
+  /// decoder signals completion by returning PP_OK or running |callback|. The
+  /// plugin can call GetPicture() again after the decoder signals completion.
+  /// When the plugin is finished using the picture, it should return it to the
+  /// system by calling RecyclePicture().
+  ///
+  /// @param[in] video_decoder A <code>PP_Resource</code> identifying the video
+  /// decoder.
+  /// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be
+  /// called on completion, and on success, to hold the picture descriptor.
+  ///
+  /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  /// Returns PP_OK if a picture is available.
+  /// Returns PP_ERROR_ABORTED when Reset() is called, or if a call to Flush()
+  /// completes while GetPicture() is pending.
+  int32_t GetPicture(
+      const CompletionCallbackWithOutput<PP_VideoPicture>& callback);
+
+  /// Recycles a picture that the plugin has received from the decoder.
+  /// The plugin should call this as soon as it has finished using the texture
+  /// so the decoder can decode more pictures.
+  ///
+  /// @param[in] picture A <code>PP_VideoPicture</code> to return to the
+  /// decoder.
+  void RecyclePicture(const PP_VideoPicture& picture);
+
+  /// Flushes the decoder. The plugin should call this when it reaches the end
+  /// of its video stream in order to stop cleanly. The decoder will run all
+  /// pending calls to completion. The plugin should make no further calls to
+  /// the decoder other than GetPicture() and RecyclePicture() until the decoder
+  /// signals completion by running the callback. Just before completion, any
+  /// pending GetPicture() call will complete by running the callback with
+  /// result PP_ERROR_ABORTED to signal that no more pictures are available.
+  ///
+  /// @param[in] callback A <code>CompletionCallback</code> to be called on
+  /// completion.
+  ///
+  /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  int32_t Flush(const CompletionCallback& callback);
+
+  /// Resets the decoder as quickly as possible. The plugin can call Reset() to
+  /// skip to another position in the video stream. Pending calls to Decode()
+  /// and GetPicture()) are immediately aborted, causing their callbacks to run
+  /// with PP_ERROR_ABORTED. The plugin should not make any further calls to the
+  /// decoder until the decoder signals completion by running |callback|.
+  ///
+  /// @param[in] callback A <code>CompletionCallback</code> to be called on
+  /// completion.
+  ///
+  /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
+  int32_t Reset(const CompletionCallback& callback);
+};
+
+}  // namespace pp
+
+#endif  // PPAPI_CPP_VIDEO_DECODER_H_