Add libvpx wrapper to media to support VP9 video decoding.

media/filters/vpx_video_decoder.h

+// Copyright (c) 2012 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 MEDIA_FILTERS_VPX_VIDEO_DECODER_H_
+#define MEDIA_FILTERS_VPX_VIDEO_DECODER_H_
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "media/base/demuxer_stream.h"
+#include "media/base/video_decoder.h"
+
+struct vpx_codec_ctx;
+struct vpx_image;
+
+namespace base {
+class MessageLoopProxy;
+}
+
+namespace media {
+
+class MEDIA_EXPORT VpxVideoDecoder : public VideoDecoder {
+ public:
+  explicit VpxVideoDecoder(
+      const scoped_refptr<base::MessageLoopProxy>& message_loop);
+
+  // VideoDecoder implementation.
+  virtual void Initialize(const scoped_refptr<DemuxerStream>& stream,
+                          const PipelineStatusCB& status_cb,
+                          const StatisticsCB& statistics_cb) OVERRIDE;
+  virtual void Read(const ReadCB& read_cb) OVERRIDE;
+  virtual void Reset(const base::Closure& closure) OVERRIDE;
+  virtual void Stop(const base::Closure& closure) OVERRIDE;
+
+ protected:
+  virtual ~VpxVideoDecoder();
+
+ private:
+  enum DecoderState {
+    kUninitialized,
+    kNormal,
+    kFlushCodec,
+    kDecodeFinished
+  };
+
+  // Handles (re-)initializing the decoder with a (new) config.
+  // Returns true when initialization was successful.
+  bool ConfigureDecoder();
+
+  void CloseDecoder();
+
+  // Carries out the buffer reading operation scheduled by Read().
+  void DoRead(const ReadCB& read_cb);
+
+  void ReadFromDemuxerStream();
+
+  // Carries out the buffer processing operation scheduled by
+  // DecryptOrDecodeBuffer().
+  void DoDecryptOrDecodeBuffer(DemuxerStream::Status status,
+                               const scoped_refptr<DecoderBuffer>& buffer);
+
+  void DecodeBuffer(const scoped_refptr<DecoderBuffer>& buffer);
+  bool Decode(const scoped_refptr<DecoderBuffer>& buffer,
+              scoped_refptr<VideoFrame>* video_frame);
+
+  // Reset decoder and call |reset_cb_|.
+  void DoReset();
+
+  bool CopyVpxImageTo(const vpx_image* vpx_image,
+                      scoped_refptr<VideoFrame>* video_frame);
+
+  scoped_refptr<base::MessageLoopProxy> message_loop_;
+
+  DecoderState state_;
+
+  StatisticsCB statistics_cb_;
+  ReadCB read_cb_;
+  base::Closure reset_cb_;
+
+  // Pointer to the demuxer stream that will feed us compressed buffers.
+  scoped_refptr<DemuxerStream> demuxer_stream_;
+
+  vpx_codec_ctx* vpx_codec_;
+
+  DISALLOW_COPY_AND_ASSIGN(VpxVideoDecoder);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_FILTERS_VPX_VIDEO_DECODER_H_