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 VP8_DECODER_H_ 6 #define VP8_DECODER_H_ 7 8 #include <stddef.h> 9 #include <stdint.h> 10 11 #include <memory> 12 13 #include "base/macros.h" 14 #include "base/memory/ref_counted.h" 15 #include "accelerated_video_decoder.h" 16 #include "size.h" 17 #include "vp8_parser.h" 18 #include "vp8_picture.h" 19 20 namespace media { 21 22 // Clients of this class are expected to pass raw VP8 stream and are expected 23 // to provide an implementation of VP8Accelerator for offloading final steps 24 // of the decoding process. 25 // 26 // This class must be created, called and destroyed on a single thread, and 27 // does nothing internally on any other thread. 28 class VP8Decoder : public AcceleratedVideoDecoder { 29 public: 30 class VP8Accelerator { 31 public: 32 VP8Accelerator(); 33 virtual ~VP8Accelerator(); 34 35 // Create a new VP8Picture that the decoder client can use for decoding 36 // and pass back to this accelerator for decoding or reference. 37 // When the picture is no longer needed by decoder, it will just drop 38 // its reference to it, and it may do so at any time. 39 // Note that this may return nullptr if accelerator is not able to provide 40 // any new pictures at given time. The decoder is expected to handle 41 // this situation as normal and return from Decode() with kRanOutOfSurfaces. 42 virtual scoped_refptr<VP8Picture> CreateVP8Picture() = 0; 43 44 // Submit decode for |pic|, taking as arguments |frame_hdr| with parsed 45 // VP8 frame header information for current frame, and using |last_frame|, 46 // |golden_frame| and |alt_frame| as references, as per VP8 specification. 47 // Note that this runs the decode in hardware. 48 // Return true if successful. 49 virtual bool SubmitDecode(const scoped_refptr<VP8Picture>& pic, 50 const Vp8FrameHeader* frame_hdr, 51 const scoped_refptr<VP8Picture>& last_frame, 52 const scoped_refptr<VP8Picture>& golden_frame, 53 const scoped_refptr<VP8Picture>& alt_frame) = 0; 54 55 // Schedule output (display) of |pic|. Note that returning from this 56 // method does not mean that |pic| has already been outputted (displayed), 57 // but guarantees that all pictures will be outputted in the same order 58 // as this method was called for them. Decoder may drop its reference 59 // to |pic| after calling this method. 60 // Return true if successful. 61 virtual bool OutputPicture(const scoped_refptr<VP8Picture>& pic) = 0; 62 63 private: 64 DISALLOW_COPY_AND_ASSIGN(VP8Accelerator); 65 }; 66 67 VP8Decoder(VP8Accelerator* accelerator); 68 ~VP8Decoder() override; 69 70 // AcceleratedVideoDecoder implementation. 71 bool Flush() override WARN_UNUSED_RESULT; 72 void Reset() override; 73 void SetStream(const uint8_t* ptr, size_t size) override; 74 DecodeResult Decode() override WARN_UNUSED_RESULT; 75 Size GetPicSize() const override; 76 size_t GetRequiredNumOfPictures() const override; 77 78 private: 79 bool DecodeAndOutputCurrentFrame(); 80 void RefreshReferenceFrames(); 81 82 enum State { 83 kNeedStreamMetadata, // After initialization, need a keyframe. 84 kDecoding, // Ready to decode from any point. 85 kAfterReset, // After Reset(), need a resume point. 86 kError, // Error in decode, can't continue. 87 }; 88 89 State state_; 90 91 Vp8Parser parser_; 92 93 std::unique_ptr<Vp8FrameHeader> curr_frame_hdr_; 94 scoped_refptr<VP8Picture> curr_pic_; 95 scoped_refptr<VP8Picture> last_frame_; 96 scoped_refptr<VP8Picture> golden_frame_; 97 scoped_refptr<VP8Picture> alt_frame_; 98 99 const uint8_t* curr_frame_start_; 100 size_t frame_size_; 101 102 Size pic_size_; 103 int horizontal_scale_; 104 int vertical_scale_; 105 106 VP8Accelerator* accelerator_; 107 108 DISALLOW_COPY_AND_ASSIGN(VP8Decoder); 109 }; 110 111 } // namespace media 112 113 #endif // VP8_DECODER_H_ 114