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] min_picture_count A count of pictures the plugin would like to
  69   /// have in flight. This is effectively the number of times the plugin can
  70   /// call GetPicture() and get a decoded frame without calling
  71   /// RecyclePicture(). The decoder has its own internal minimum count, and will
  72   /// take the larger of its internal and this value. A client that doesn't care
  73   /// can therefore just pass in zero for this argument.
  74   /// @param[in] callback A <code>PP_CompletionCallback</code> to be called upon
  75   /// completion.
  76   ///
  77   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
  78   /// Returns PP_ERROR_NOTSUPPORTED if video decoding is not available, or the
  79   /// requested profile is not supported. In this case, the client may call
  80   /// Initialize() again with different parameters to find a good configuration.
  81   int32_t Initialize(const Graphics3D& graphics3d_context,
  82                      PP_VideoProfile profile,
  83                      PP_HardwareAcceleration acceleration,
  84                      uint32_t min_picture_count,
  85                      const CompletionCallback& callback);
  86
  87   /// Decodes a bitstream buffer. Copies |size| bytes of data from the plugin's
  88   /// |buffer|. The plugin should wait until the decoder signals completion by
  89   /// returning PP_OK or by running |callback| before calling Decode() again.
  90   ///
  91   /// In general, each bitstream buffer should contain a demuxed bitstream frame
  92   /// for the selected video codec. For example, H264 decoders expect to receive
  93   /// one AnnexB NAL unit, including the 4 byte start code prefix, while VP8
  94   /// decoders expect to receive a bitstream frame without the IVF frame header.
  95   ///
  96   /// If the call to Decode() eventually results in a picture, the |decode_id|
  97   /// parameter is copied into the returned picture. The plugin can use this to
  98   /// associate decoded pictures with Decode() calls (e.g. to assign timestamps
  99   /// or frame numbers to pictures.) This value is opaque to the API so the
 100   /// plugin is free to pass any value.
 101   ///
 102   /// @param[in] decode_id An optional value, chosen by the plugin, that can be
 103   /// used to associate calls to Decode() with decoded pictures returned by
 104   /// GetPicture().
 105   /// @param[in] size Buffer size in bytes.
 106   /// @param[in] buffer Starting address of buffer.
 107   /// @param[in] callback A <code>CompletionCallback</code> to be called on
 108   /// completion.
 109   ///
 110   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 111   /// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Flush()
 112   /// or Reset() call is pending.
 113   /// Returns PP_ERROR_INPROGRESS if there is another Decode() call pending.
 114   /// Returns PP_ERROR_NOMEMORY if a bitstream buffer can't be created.
 115   /// Returns PP_ERROR_ABORTED when Reset() is called while Decode() is pending.
 116   int32_t Decode(uint32_t decode_id,
 117                  uint32_t size,
 118                  const void* buffer,
 119                  const CompletionCallback& callback);
 120
 121   /// Gets the next picture from the decoder. The picture is valid after the
 122   /// decoder signals completion by returning PP_OK or running |callback|. The
 123   /// plugin can call GetPicture() again after the decoder signals completion.
 124   /// When the plugin is finished using the picture, it should return it to the
 125   /// system by calling RecyclePicture().
 126   ///
 127   /// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be
 128   /// called on completion, and on success, to hold the picture descriptor.
 129   ///
 130   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 131   /// Returns PP_ERROR_FAILED if the decoder isn't initialized or if a Reset()
 132   /// call is pending.
 133   /// Returns PP_ERROR_INPROGRESS if there is another GetPicture() call pending.
 134   /// Returns PP_ERROR_ABORTED when Reset() is called, or if a call to Flush()
 135   /// completes while GetPicture() is pending.
 136   int32_t GetPicture(
 137       const CompletionCallbackWithOutput<PP_VideoPicture>& callback);
 138
 139   /// Recycles a picture that the plugin has received from the decoder.
 140   /// The plugin should call this as soon as it has finished using the texture
 141   /// so the decoder can decode more pictures.
 142   ///
 143   /// @param[in] picture A <code>PP_VideoPicture</code> to return to the
 144   /// decoder.
 145   void RecyclePicture(const PP_VideoPicture& picture);
 146
 147   /// Flushes the decoder. The plugin should call Flush() when it reaches the
 148   /// end of its video stream in order to stop cleanly. The decoder will run any
 149   /// pending Decode() call to completion. The plugin should make no further
 150   /// calls to the decoder other than GetPicture() and RecyclePicture() until
 151   /// the decoder signals completion by running |callback|. Just before
 152   /// completion, any pending GetPicture() call will complete by running its
 153   /// callback with result PP_ERROR_ABORTED to signal that no more pictures are
 154   /// available. Any pictures held by the plugin remain valid during and after
 155   /// the flush and should be recycled back to the decoder.
 156   ///
 157   /// @param[in] callback A <code>CompletionCallback</code> to be called on
 158   /// completion.
 159   ///
 160   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 161   /// Returns PP_ERROR_FAILED if the decoder isn't initialized.
 162   int32_t Flush(const CompletionCallback& callback);
 163
 164   /// Resets the decoder as quickly as possible. The plugin can call Reset() to
 165   /// skip to another position in the video stream. After Reset() returns, any
 166   /// pending calls to Decode() and GetPicture()) abort, causing their callbacks
 167   /// to run with PP_ERROR_ABORTED. The plugin should not make further calls to
 168   /// the decoder other than RecyclePicture() until the decoder signals
 169   /// completion by running |callback|. Any pictures held by the plugin remain
 170   /// valid during and after the reset and should be recycled back to the
 171   /// decoder.
 172   ///
 173   /// @param[in] callback A <code>CompletionCallback</code> to be called on
 174   /// completion.
 175   ///
 176   /// @return An int32_t containing an error code from <code>pp_errors.h</code>.
 177     /// Returns PP_ERROR_FAILED if the decoder isn't initialized.
 178 int32_t Reset(const CompletionCallback& callback);
 179 };
 180
 181 }  // namespace pp
 182
 183 #endif  // PPAPI_CPP_VIDEO_DECODER_H_