blob: 2de51d4663cab8b34aa47a331a6c82302d51fd62 [file] [log] [blame]
// Copyright 2014 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.
#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "base/threading/thread_checker.h"
#include "media/cast/cast_config.h"
#include "media/cast/sender/software_video_encoder.h"
#include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
#include "ui/gfx/geometry/size.h"
namespace media {
class VideoFrame;
namespace media {
namespace cast {
class Vp8Encoder : public SoftwareVideoEncoder {
explicit Vp8Encoder(const VideoSenderConfig& video_config);
~Vp8Encoder() override;
// SoftwareVideoEncoder implementations.
void Initialize() override;
void Encode(const scoped_refptr<media::VideoFrame>& video_frame,
const base::TimeTicks& reference_time,
EncodedFrame* encoded_frame) override;
void UpdateRates(uint32 new_bitrate) override;
void GenerateKeyFrame() override;
void LatestFrameIdToReference(uint32 frame_id) override;
enum { kNumberOfVp8VideoBuffers = 3 };
enum Vp8Buffers {
kAltRefBuffer = 0,
kGoldenBuffer = 1,
kLastBuffer = 2,
kNoBuffer = 3 // Note: must be last.
enum Vp8BufferState {
struct BufferState {
uint32 frame_id;
Vp8BufferState state;
bool is_initialized() const {
// ConfigureForNewFrameSize() sets the timebase denominator value to
// non-zero if the encoder is successfully initialized, and it is zero
// otherwise.
return config_.g_timebase.den != 0;
// If the |encoder_| is live, attempt reconfiguration to allow it to encode
// frames at a new |frame_size|. Otherwise, tear it down and re-create a new
// |encoder_| instance.
void ConfigureForNewFrameSize(const gfx::Size& frame_size);
// Calculate which next Vp8 buffers to update with the next frame.
Vp8Buffers GetNextBufferToUpdate();
// Get encoder flags for our referenced encoder buffers.
// Return which previous frame to reference.
uint32 GetCodecReferenceFlags(vpx_codec_flags_t* flags);
// Get encoder flags for our encoder buffers to update with next frame.
void GetCodecUpdateFlags(Vp8Buffers buffer_to_update,
vpx_codec_flags_t* flags);
const VideoSenderConfig cast_config_;
const bool use_multiple_video_buffers_;
// VP8 internal objects. These are valid for use only while is_initialized()
// returns true.
vpx_codec_enc_cfg_t config_;
vpx_codec_ctx_t encoder_;
// Set to true to request the next frame emitted by Vp8Encoder be a key frame.
bool key_frame_requested_;
// Saves the current bitrate setting, for when the |encoder_| is reconfigured
// for different frame sizes.
int bitrate_kbit_;
// The |VideoFrame::timestamp()| of the last encoded frame. This is used to
// predict the duration of the next frame.
base::TimeDelta last_frame_timestamp_;
// The last encoded frame's ID.
uint32 last_encoded_frame_id_;
// Used to track which buffers are old enough to be re-used.
uint32 last_acked_frame_id_;
// Used by GetNextBufferToUpdate() to track how many consecutive times the
// newest buffer had to be overwritten.
int undroppable_frames_;
// Tracks the lifecycle and dependency state of each of the three buffers.
BufferState buffer_state_[kNumberOfVp8VideoBuffers];
// This is bound to the thread where Initialize() is called.
base::ThreadChecker thread_checker_;
} // namespace cast
} // namespace media