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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef VP9_DECODER_H_
#define VP9_DECODER_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include <vector>
#include "base/callback_forward.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "accelerated_video_decoder.h"
#include "vp9_parser.h"
#include "vp9_picture.h"
namespace media {
// This class implements an AcceleratedVideoDecoder for VP9 decoding.
// Clients of this class are expected to pass raw VP9 stream and are expected
// to provide an implementation of VP9Accelerator for offloading final steps
// of the decoding process.
//
// This class must be created, called and destroyed on a single thread, and
// does nothing internally on any other thread.
class VP9Decoder : public AcceleratedVideoDecoder {
public:
class VP9Accelerator {
public:
VP9Accelerator();
virtual ~VP9Accelerator();
// Create a new VP9Picture that the decoder client can use for initial
// stages of the decoding process and pass back to this accelerator for
// final, accelerated stages of it, or for reference when decoding other
// pictures.
//
// When a picture is no longer needed by the decoder, it will just drop
// its reference to it, and it may do so at any time.
//
// Note that this may return nullptr if the accelerator is not able to
// provide any new pictures at the given time. The decoder must handle this
// case and treat it as normal, returning kRanOutOfSurfaces from Decode().
virtual scoped_refptr<VP9Picture> CreateVP9Picture() = 0;
// Submit decode for |pic| to be run in accelerator, taking as arguments
// information contained in it, as well as current segmentation and loop
// filter state in |segm_params| and |lf_params|, respectively, and using
// pictures in |ref_pictures| for reference.
// If done_cb_ is not null, it will be run once decode is done in hardware.
//
// Note that returning from this method does not mean that the decode
// process is finished, but the caller may drop its references to |pic|
// and |ref_pictures| immediately, and the data in |segm_params| and
// |lf_params| does not need to remain valid after this method returns.
//
// Return true when successful, false otherwise.
virtual bool SubmitDecode(
const scoped_refptr<VP9Picture>& pic,
const Vp9SegmentationParams& segm_params,
const Vp9LoopFilterParams& lf_params,
const std::vector<scoped_refptr<VP9Picture>>& ref_pictures,
const base::Closure& done_cb) = 0;
// Schedule output (display) of |pic|.
//
// Note that returning from this method does not mean that |pic| has already
// been outputted (displayed), but guarantees that all pictures will be
// outputted in the same order as this method was called for them, and that
// they are decoded before outputting (assuming SubmitDecode() has been
// called for them beforehand). Decoder may drop its references to |pic|
// immediately after calling this method.
//
// Return true when successful, false otherwise.
virtual bool OutputPicture(const scoped_refptr<VP9Picture>& pic) = 0;
// Return true if the accelerator requires the client to provide frame
// context in order to decode. If so, the Vp9FrameHeader provided by the
// client must contain a valid compressed header and frame context data.
virtual bool IsFrameContextRequired() const = 0;
// Set |frame_ctx| to the state after decoding |pic|, returning true on
// success, false otherwise.
virtual bool GetFrameContext(const scoped_refptr<VP9Picture>& pic,
Vp9FrameContext* frame_ctx) = 0;
private:
DISALLOW_COPY_AND_ASSIGN(VP9Accelerator);
};
explicit VP9Decoder(VP9Accelerator* accelerator);
~VP9Decoder() override;
// AcceleratedVideoDecoder implementation.
void SetStream(const uint8_t* ptr, size_t size) override;
bool Flush() override WARN_UNUSED_RESULT;
void Reset() override;
DecodeResult Decode() override WARN_UNUSED_RESULT;
Size GetPicSize() const override;
size_t GetRequiredNumOfPictures() const override;
private:
// Update ref_frames_ based on the information in current frame header.
void RefreshReferenceFrames(const scoped_refptr<VP9Picture>& pic);
// Decode and possibly output |pic| (if the picture is to be shown).
// Return true on success, false otherwise.
bool DecodeAndOutputPicture(scoped_refptr<VP9Picture> pic);
// Get frame context state after decoding |pic| from the accelerator, and call
// |context_refresh_cb| with the acquired state.
void UpdateFrameContext(
const scoped_refptr<VP9Picture>& pic,
const base::Callback<void(const Vp9FrameContext&)>& context_refresh_cb);
// Called on error, when decoding cannot continue. Sets state_ to kError and
// releases current state.
void SetError();
enum State {
kNeedStreamMetadata, // After initialization, need a keyframe.
kDecoding, // Ready to decode from any point.
kAfterReset, // After Reset(), need a resume point.
kError, // Error in decode, can't continue.
};
// Current decoder state.
State state_;
// Current frame header to be used in decoding the next picture.
std::unique_ptr<Vp9FrameHeader> curr_frame_hdr_;
// Reference frames currently in use.
std::vector<scoped_refptr<VP9Picture>> ref_frames_;
// Current coded resolution.
Size pic_size_;
// VP9Accelerator instance owned by the client.
VP9Accelerator* accelerator_;
Vp9Parser parser_;
DISALLOW_COPY_AND_ASSIGN(VP9Decoder);
};
} // namespace media
#endif // VP9_DECODER_H_
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