content/common/gpu/media/vp8_decoder.h

   1 // Copyright 2015 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 CONTENT_COMMON_GPU_MEDIA_VP8_DECODER_H_
   6 #define CONTENT_COMMON_GPU_MEDIA_VP8_DECODER_H_
   7
   8 #include "base/memory/ref_counted.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "content/common/gpu/media/accelerated_video_decoder.h"
  11 #include "content/common/gpu/media/vp8_picture.h"
  12 #include "media/filters/vp8_parser.h"
  13
  14 namespace content {
  15
  16 // Clients of this class are expected to pass raw VP8 stream and are expected
  17 // to provide an implementation of VP8Accelerator for offloading final steps
  18 // of the decoding process.
  19 //
  20 // This class must be created, called and destroyed on a single thread, and
  21 // does nothing internally on any other thread.
  22 class CONTENT_EXPORT VP8Decoder : public AcceleratedVideoDecoder {
  23  public:
  24   class CONTENT_EXPORT VP8Accelerator {
  25    public:
  26     VP8Accelerator();
  27     virtual ~VP8Accelerator();
  28
  29     // Create a new VP8Picture that the decoder client can use for decoding
  30     // and pass back to this accelerator for decoding or reference.
  31     // When the picture is no longer needed by decoder, it will just drop
  32     // its reference to it, and it may do so at any time.
  33     // Note that this may return nullptr if accelerator is not able to provide
  34     // any new pictures at given time. The decoder is expected to handle
  35     // this situation as normal and return from Decode() with kRanOutOfSurfaces.
  36     virtual scoped_refptr<VP8Picture> CreateVP8Picture() = 0;
  37
  38     // Submit decode for |pic|, taking as arguments |frame_hdr| with parsed
  39     // VP8 frame header information for current frame, and using |last_frame|,
  40     // |golden_frame| and |alt_frame| as references, as per VP8 specification.
  41     // Note that this runs the decode in hardware.
  42     // Return true if successful.
  43     virtual bool SubmitDecode(const scoped_refptr<VP8Picture>& pic,
  44                               const media::Vp8FrameHeader* frame_hdr,
  45                               const scoped_refptr<VP8Picture>& last_frame,
  46                               const scoped_refptr<VP8Picture>& golden_frame,
  47                               const scoped_refptr<VP8Picture>& alt_frame) = 0;
  48
  49     // Schedule output (display) of |pic|. Note that returning from this
  50     // method does not mean that |pic| has already been outputted (displayed),
  51     // but guarantees that all pictures will be outputted in the same order
  52     // as this method was called for them. Decoder may drop its reference
  53     // to |pic| after calling this method.
  54     // Return true if successful.
  55     virtual bool OutputPicture(const scoped_refptr<VP8Picture>& pic) = 0;
  56
  57    private:
  58     DISALLOW_COPY_AND_ASSIGN(VP8Accelerator);
  59   };
  60
  61   VP8Decoder(VP8Accelerator* accelerator);
  62   ~VP8Decoder() override;
  63
  64   // content::AcceleratedVideoDecoder implementation.
  65   bool Flush() override WARN_UNUSED_RESULT;
  66   void Reset() override;
  67   void SetStream(const uint8_t* ptr, size_t size) override;
  68   DecodeResult Decode() override WARN_UNUSED_RESULT;
  69   gfx::Size GetPicSize() const override;
  70   size_t GetRequiredNumOfPictures() const override;
  71
  72  private:
  73   bool DecodeAndOutputCurrentFrame();
  74   void RefreshReferenceFrames();
  75
  76   enum State {
  77     kNeedStreamMetadata,  // After initialization, need a keyframe.
  78     kDecoding,            // Ready to decode from any point.
  79     kAfterReset,          // After Reset(), need a resume point.
  80     kError,               // Error in decode, can't continue.
  81   };
  82
  83   State state_;
  84
  85   media::Vp8Parser parser_;
  86
  87   scoped_ptr<media::Vp8FrameHeader> curr_frame_hdr_;
  88   scoped_refptr<VP8Picture> curr_pic_;
  89   scoped_refptr<VP8Picture> last_frame_;
  90   scoped_refptr<VP8Picture> golden_frame_;
  91   scoped_refptr<VP8Picture> alt_frame_;
  92
  93   const uint8_t* curr_frame_start_;
  94   size_t frame_size_;
  95
  96   gfx::Size pic_size_;
  97   int horizontal_scale_;
  98   int vertical_scale_;
  99
 100   VP8Accelerator* accelerator_;
 101
 102   DISALLOW_COPY_AND_ASSIGN(VP8Decoder);
 103 };
 104
 105 }  // namespace content
 106
 107 #endif  // CONTENT_COMMON_GPU_MEDIA_VP8_DECODER_H_