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