remoting/codec/video_decoder.h

   1 // Copyright (c) 2012 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 REMOTING_CODEC_VIDEO_DECODER_H_
   6 #define REMOTING_CODEC_VIDEO_DECODER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "remoting/proto/video.pb.h"
  10
  11 namespace webrtc {
  12 class DesktopRect;
  13 class DesktopRegion;
  14 class DesktopSize;
  15 }  // namespace webrtc
  16
  17 namespace remoting {
  18
  19 // Interface for a decoder that takes a stream of bytes from the network and
  20 // outputs frames of data.
  21 class VideoDecoder {
  22  public:
  23   static const int kBytesPerPixel = 4;
  24
  25   VideoDecoder() {}
  26   virtual ~VideoDecoder() {}
  27
  28   // Initializes the decoder and sets the output dimensions.
  29   // |screen size| must not be empty.
  30   virtual void Initialize(const webrtc::DesktopSize& screen_size) = 0;
  31
  32   // Feeds more data into the decoder. Returns true if |packet| was processed
  33   // and the frame can be displayed now.
  34   virtual bool DecodePacket(const VideoPacket& packet) = 0;
  35
  36   // Marks the specified |region| of the view for update the next time
  37   // RenderFrame() is called.  |region| is expressed in |view_size| coordinates.
  38   // |view_size| must not be empty.
  39   virtual void Invalidate(const webrtc::DesktopSize& view_size,
  40                           const webrtc::DesktopRegion& region) = 0;
  41
  42   // Copies invalidated pixels within |clip_area| to |image_buffer|. Pixels are
  43   // invalidated either by new data received in DecodePacket(), or by explicit
  44   // calls to Invalidate(). |clip_area| is specified in |view_size| coordinates.
  45   // If |view_size| differs from the source size then the copied pixels will be
  46   // scaled accordingly. |view_size| cannot be empty.
  47   //
  48   // |image_buffer|'s origin must correspond to the top-left of |clip_area|,
  49   // and the buffer must be large enough to hold |clip_area| RGBA32 pixels.
  50   // |image_stride| gives the output buffer's stride in pixels.
  51   //
  52   // On return, |output_region| contains the updated area, in |view_size|
  53   // coordinates.
  54   virtual void RenderFrame(const webrtc::DesktopSize& view_size,
  55                            const webrtc::DesktopRect& clip_area,
  56                            uint8* image_buffer,
  57                            int image_stride,
  58                            webrtc::DesktopRegion* output_region) = 0;
  59
  60   // Returns the "shape", if any, of the most recently rendered frame.
  61   // The shape is returned in source dimensions.
  62   virtual const webrtc::DesktopRegion* GetImageShape() = 0;
  63 };
  64
  65 }  // namespace remoting
  66
  67 #endif  // REMOTING_CODEC_VIDEO_DECODER_H_