Reland: Add accelerated VP9 decode infrastructure and an implementation for VA-API.

content/common/gpu/media/vp9_decoder.h

+// 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 CONTENT_COMMON_GPU_MEDIA_VP9_DECODER_H_
+#define CONTENT_COMMON_GPU_MEDIA_VP9_DECODER_H_
+
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "content/common/gpu/media/accelerated_video_decoder.h"
+#include "content/common/gpu/media/vp9_picture.h"
+#include "media/filters/vp9_parser.h"
+
+namespace content {
+
+// 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 CONTENT_EXPORT VP9Decoder : public AcceleratedVideoDecoder {
+ public:
+  class CONTENT_EXPORT 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 |seg| and |lf|, respectively, and using pictures in
+    // |ref_pictures| for reference.
+    //
+    // 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 |seg| and |lf| 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 media::Vp9Segmentation& seg,
+        const media::Vp9LoopFilter& lf,
+        const std::vector<scoped_refptr<VP9Picture>>& ref_pictures) = 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;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(VP9Accelerator);
+  };
+
+  VP9Decoder(VP9Accelerator* accelerator);
+  ~VP9Decoder() override;
+
+  // content::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;
+  gfx::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);
+
+  // 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.
+  scoped_ptr<media::Vp9FrameHeader> curr_frame_hdr_;
+
+  // Reference frames currently in use.
+  std::vector<scoped_refptr<VP9Picture>> ref_frames_;
+
+  // Current coded resolution.
+  gfx::Size pic_size_;
+
+  media::Vp9Parser parser_;
+
+  // VP9Accelerator instance owned by the client.
+  VP9Accelerator* accelerator_;
+
+  DISALLOW_COPY_AND_ASSIGN(VP9Decoder);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_VP9_DECODER_H_