Refactor VideoTrackRecorder into smaller classes

content/renderer/media_recorder/vpx_encoder.h

+// Copyright 2017 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_RENDERER_MEDIA_RECORDER_VPX_ENCODER_H_
+#define CONTENT_RENDERER_MEDIA_RECORDER_VPX_ENCODER_H_
+
+#include <vector>
+
+#include "content/renderer/media_recorder/video_track_recorder.h"
+
+extern "C" {
+// VPX_CODEC_DISABLE_COMPAT excludes parts of the libvpx API that provide
+// backwards compatibility for legacy applications using the library.
+#define VPX_CODEC_DISABLE_COMPAT 1
+#include "third_party/libvpx/source/libvpx/vpx/vp8cx.h"
+#include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
+}
+
+namespace content {
+
+// Class encapsulating all libvpx interactions for VP8/VP9 encoding.
+class VpxEncoder final : public VideoTrackRecorder::Encoder {
+ public:
+  // Originally from remoting/codec/scoped_vpx_codec.h.
+  // TODO(mcasas): Refactor into a common location.
+  struct VpxCodecDeleter {
+    void operator()(vpx_codec_ctx_t* codec);
+  };
+  typedef std::unique_ptr<vpx_codec_ctx_t, VpxCodecDeleter>
+      ScopedVpxCodecCtxPtr;
+
+  static void ShutdownEncoder(std::unique_ptr<base::Thread> encoding_thread,
+                              ScopedVpxCodecCtxPtr encoder);
+
+  VpxEncoder(
+      bool use_vp9,
+      const VideoTrackRecorder::OnEncodedVideoCB& on_encoded_video_callback,
+      int32_t bits_per_second);
+
+ private:
+  // VideoTrackRecorder::Encoder implementation.
+  ~VpxEncoder() override;
+  void EncodeOnEncodingTaskRunner(scoped_refptr<media::VideoFrame> frame,
+                                  base::TimeTicks capture_timestamp) override;
+  bool CanEncodeAlphaChannel() override;
+
+  void ConfigureEncoderOnEncodingTaskRunner(const gfx::Size& size,
+                                            vpx_codec_enc_cfg_t* codec_config,
+                                            ScopedVpxCodecCtxPtr* encoder);
+  void DoEncode(vpx_codec_ctx_t* const encoder,
+                const gfx::Size& frame_size,
+                uint8_t* const data,
+                uint8_t* const y_plane,
+                int y_stride,
+                uint8_t* const u_plane,
+                int u_stride,
+                uint8_t* const v_plane,
+                int v_stride,
+                const base::TimeDelta& duration,
+                bool force_keyframe,
+                std::string* const output_data,
+                bool* const keyframe);
+
+  // Returns true if |codec_config| has been filled in at least once.
+  bool IsInitialized(const vpx_codec_enc_cfg_t& codec_config) const;
+
+  // Estimate the frame duration from |frame| and |last_frame_timestamp_|.
+  base::TimeDelta EstimateFrameDuration(
+      const scoped_refptr<media::VideoFrame>& frame);
+
+  // Force usage of VP9 for encoding, instead of VP8 which is the default.
+  const bool use_vp9_;
+
+  // VPx internal objects: configuration and encoder. |encoder_| is a special
+  // scoped pointer to guarantee proper destruction, particularly when
+  // reconfiguring due to parameters change. Only used on
+  // VideoTrackRecorder::Encoder::encoding_thread_.
+  vpx_codec_enc_cfg_t codec_config_;
+  ScopedVpxCodecCtxPtr encoder_;
+
+  vpx_codec_enc_cfg_t alpha_codec_config_;
+  ScopedVpxCodecCtxPtr alpha_encoder_;
+
+  std::vector<uint8_t> alpha_dummy_planes_;
+  size_t v_plane_offset_;
+  size_t u_plane_stride_;
+  size_t v_plane_stride_;
+  bool last_frame_had_alpha_ = false;
+
+  // The |media::VideoFrame::timestamp()| of the last encoded frame.  This is
+  // used to predict the duration of the next frame. Only used on
+  // VideoTrackRecorder::Encoder::encoding_thread_.
+  base::TimeDelta last_frame_timestamp_;
+
+  DISALLOW_COPY_AND_ASSIGN(VpxEncoder);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_MEDIA_RECORDER_VPX_ENCODER_H_