ppapi/cpp/video_decoder.h

   1 // Copyright (c) 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 #ifndef PPAPI_CPP_VIDEO_DECODER_H_
   6 #define PPAPI_CPP_VIDEO_DECODER_H_
   7
   8 #include "ppapi/c/pp_codecs.h"
   9 #include "ppapi/c/pp_size.h"
  10 #include "ppapi/cpp/completion_callback.h"
  11 #include "ppapi/cpp/graphics_3d.h"
  12 #include "ppapi/cpp/resource.h"
  13 #include "ppapi/cpp/size.h"
  14
  15 /// @file
  16 /// This file defines the API to create and use a VideoDecoder resource.
  17
  18 struct PP_FileInfo;
  19
  20 namespace pp {
  21
  22 class InstanceHandle;
  23
  24 /// Video decoder interface.
  25 ///
  26 /// Typical usage:
  27 /// - Call Create() to create a new video decoder resource.
  28 /// - Call Initialize() to initialize it with a 3d graphics context and the
  29 ///   desired codec profile.
  30 /// - Call Decode() continuously (waiting for each previous call to complete) to
  31 ///   push bitstream buffers to the decoder.
  32 /// - Call GetPicture() continuously (waiting for each previous call to
  33 ///   complete) to pull decoded pictures from the decoder.
  34 /// - Call Flush() to signal end of stream to the decoder and perform shutdown
  35 ///   when it completes.
  36 /// - Call Reset() to quickly stop the decoder (e.g. to implement Seek) and wait
  37 ///   for the callback before restarting decoding at another point.
  38 /// - To destroy the decoder, the plugin should release all of its references to
  39 ///   it. Any pending callbacks will abort before the decoder is destroyed.
  40 ///
  41 /// Available video codecs vary by platform.
  42 /// All: theora, vorbis, vp8.
  43 /// Chrome and ChromeOS: aac, h264.
  44 /// ChromeOS: mpeg4.
  45 class VideoDecoder : public Resource {
  46  public:
  47   /// Default constructor for creating an is_null() <code>VideoDecoder</code>
  48   /// object.
  49   VideoDecoder();
  50
  51   /// A constructor used to create a <code>VideoDecoder</code> and associate it
  52   /// with the provided <code>Instance</code>.
  53   /// @param[in] instance The instance with which this resource will be
  54   /// associated.
  55   explicit VideoDecoder(const InstanceHandle& instance);
  56
  57   /// The copy constructor for <code>VideoDecoder</code>.
  58   /// @param[in] other A reference to a <code>VideoDecoder</code>.
  59   VideoDecoder(const VideoDecoder& other);
  60
  61   /// Initializes a video decoder resource. This should be called after Create()
  62   /// and before any other functions.
  63   ///
  64   /// @param[in] graphics3d_context A <code>PPB_Graphics3D</code> resource to
  65   /// use during decoding.
  66   /// @param[in] profile A <code>PP_VideoProfile</code> specifying the video
  67   /// codec profile.
  68   /// @param[in] acceleration A <code>PP_HardwareAcceleration</code> specifying
  69   /// whether to use a hardware accelerated or a software implementation.
  70   /// @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
  71   /// completion.
  72   ///
  73   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
  74   /// Returns PP_ERROR_NOTSUPPORTED if video decoding is not available, or the
  75   /// requested profile is not supported. In this case, the client may call
  76   /// Initialize() again with different parameters to find a good configuration.
  77   int32_t Initialize(const Graphics3D& graphics3d_context,
  78                      PP_VideoProfile profile,
  79                      PP_HardwareAcceleration acceleration,
  80                      const CompletionCallback& callback);
  81
  82   /// Decodes a bitstream buffer. Copies |size| bytes of data from the plugin's
  83   /// |buffer|. The plugin should wait until the decoder signals completion by
  84   /// returning PP_OK or by running |callback| before calling Decode() again.
  85   ///
  86   /// In general, each bitstream buffer should contain a demuxed bitstream frame
  87   /// for the selected video codec. For example, H264 decoders expect to receive
  88   /// one AnnexB NAL unit, including the 4 byte start code prefix, while VP8
  89   /// decoders expect to receive a bitstream frame without the IVF frame header.
  90   ///
  91   /// If the call to Decode() eventually results in a picture, the |decode_id|
  92   /// parameter is copied into the returned picture. The plugin can use this to
  93   /// associate decoded pictures with Decode() calls (e.g. to assign timestamps
  94   /// or frame numbers to pictures.) This value is opaque to the API so the
  95   /// plugin is free to pass any value.
  96   ///
  97   /// @param[in] decode_id An optional value, chosen by the plugin, that can be
  98   /// used to associate calls to Decode() with decoded pictures returned by
  99   /// GetPicture().
 100   /// @param[in] size Buffer size in bytes.
 101   /// @param[in] buffer Starting address of buffer.
 102   /// @param[in] callback A <code>CompletionCallback</code> to be called on
 103   /// completion.
 104   ///
 105   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 106   /// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Flush()
 107   /// or Reset() call is pending.
 108   /// Returns PP_ERROR_INPROGRESS if there is another Decode() call pending.
 109   /// Returns PP_ERROR_NOMEMORY if a bitstream buffer can't be created.
 110   /// Returns PP_ERROR_ABORTED when Reset() is called while Decode() is pending.
 111   int32_t Decode(uint32_t decode_id,
 112                  uint32_t size,
 113                  const void* buffer,
 114                  const CompletionCallback& callback);
 115
 116   /// Gets the next picture from the decoder. The picture is valid after the
 117   /// decoder signals completion by returning PP_OK or running |callback|. The
 118   /// plugin can call GetPicture() again after the decoder signals completion.
 119   /// When the plugin is finished using the picture, it should return it to the
 120   /// system by calling RecyclePicture().
 121   ///
 122   /// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be
 123   /// called on completion, and on success, to hold the picture descriptor.
 124   ///
 125   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 126   /// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Reset()
 127   /// call is pending.
 128   /// Returns PP_ERROR_INPROGRESS if there is another GetPicture() call pending.
 129   /// Returns PP_ERROR_ABORTED when Reset() is called, or if a call to Flush()
 130   /// completes while GetPicture() is pending.
 131   int32_t GetPicture(
 132       const CompletionCallbackWithOutput<PP_VideoPicture>& callback);
 133
 134   /// Recycles a picture that the plugin has received from the decoder.
 135   /// The plugin should call this as soon as it has finished using the texture
 136   /// so the decoder can decode more pictures.
 137   ///
 138   /// @param[in] picture A <code>PP_VideoPicture</code> to return to the
 139   /// decoder.
 140   void RecyclePicture(const PP_VideoPicture& picture);
 141
 142   /// Flushes the decoder. The plugin should call Flush() when it reaches the
 143   /// end of its video stream in order to stop cleanly. The decoder will run any
 144   /// pending Decode() call to completion. The plugin should make no further
 145   /// calls to the decoder other than GetPicture() and RecyclePicture() until
 146   /// the decoder signals completion by running |callback|. Just before
 147   /// completion, any pending GetPicture() call will complete by running its
 148   /// callback with result PP_ERROR_ABORTED to signal that no more pictures are
 149   /// available. Any pictures held by the plugin remain valid during and after
 150   /// the flush and should be recycled back to the decoder.
 151   ///
 152   /// @param[in] callback A <code>CompletionCallback</code> to be called on
 153   /// completion.
 154   ///
 155   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 156   /// Returns PP_ERROR_FAILED if the decoder isn't initialized.
 157   int32_t Flush(const CompletionCallback& callback);
 158
 159   /// Resets the decoder as quickly as possible. The plugin can call Reset() to
 160   /// skip to another position in the video stream. After Reset() returns, any
 161   /// pending calls to Decode() and GetPicture()) abort, causing their callbacks
 162   /// to run with PP_ERROR_ABORTED. The plugin should not make further calls to
 163   /// the decoder other than RecyclePicture() until the decoder signals
 164   /// completion by running |callback|. Any pictures held by the plugin remain
 165   /// valid during and after the reset and should be recycled back to the
 166   /// decoder.
 167   ///
 168   /// @param[in] callback A <code>CompletionCallback</code> to be called on
 169   /// completion.
 170   ///
 171   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 172     /// Returns PP_ERROR_FAILED if the decoder isn't initialized.
 173 int32_t Reset(const CompletionCallback& callback);
 174 };
 175
 176 }  // namespace pp
 177
 178 #endif  // PPAPI_CPP_VIDEO_DECODER_H_