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// 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.
#ifndef MEDIA_CAST_SENDER_H264_VT_ENCODER_H_
#define MEDIA_CAST_SENDER_H264_VT_ENCODER_H_
#include <stdint.h>
#include "base/mac/scoped_cftyperef.h"
#include "base/macros.h"
#include "base/power_monitor/power_observer.h"
#include "base/threading/thread_checker.h"
#include "media/base/mac/videotoolbox_helpers.h"
#include "media/cast/sender/size_adaptable_video_encoder_base.h"
#include "media/cast/sender/video_encoder.h"
namespace media {
namespace cast {
// VideoToolbox implementation of the media::cast::VideoEncoder interface.
// VideoToolbox makes no guarantees that it is thread safe, so this object is
// pinned to the thread on which it is constructed. Supports changing frame
// sizes directly. Implements the base::PowerObserver interface to reset the
// compression session when the host process is suspended.
class H264VideoToolboxEncoder final : public VideoEncoder,
public base::PowerSuspendObserver {
public:
// Returns true if the current platform and system configuration supports
// using H264VideoToolboxEncoder with the given |video_config|.
static bool IsSupported(const FrameSenderConfig& video_config);
H264VideoToolboxEncoder(
const scoped_refptr<CastEnvironment>& cast_environment,
const FrameSenderConfig& video_config,
StatusChangeCallback status_change_cb);
H264VideoToolboxEncoder(const H264VideoToolboxEncoder&) = delete;
H264VideoToolboxEncoder& operator=(const H264VideoToolboxEncoder&) = delete;
~H264VideoToolboxEncoder() override;
// media::cast::VideoEncoder implementation
bool EncodeVideoFrame(scoped_refptr<media::VideoFrame> video_frame,
base::TimeTicks reference_time,
FrameEncodedCallback frame_encoded_callback) override;
void SetBitRate(int new_bit_rate) override;
void GenerateKeyFrame() override;
std::unique_ptr<VideoFrameFactory> CreateVideoFrameFactory() override;
void EmitFrames() override;
// base::PowerSuspendObserver
void OnSuspend() override;
void OnResume() override;
private:
// VideoFrameFactory tied to the VideoToolbox encoder.
class VideoFrameFactoryImpl;
// Reset the encoder's compression session by destroying the existing one
// using DestroyCompressionSession() and creating a new one. The new session
// is configured using ConfigureCompressionSession().
void ResetCompressionSession();
// Configure the current compression session using current encoder settings.
void ConfigureCompressionSession();
// Destroy the current compression session if any. Blocks until all pending
// frames have been flushed out (similar to EmitFrames without doing any
// encoding work).
void DestroyCompressionSession();
// Update the encoder's target frame size by resetting the compression
// session. This will also update the video frame factory.
void UpdateFrameSize(const gfx::Size& size_needed);
// Compression session callback function to handle compressed frames.
static void CompressionCallback(void* encoder_opaque,
void* request_opaque,
OSStatus status,
VTEncodeInfoFlags info,
CMSampleBufferRef sbuf);
// The cast environment (contains worker threads & more).
const scoped_refptr<CastEnvironment> cast_environment_;
// VideoSenderConfig copy so we can create compression sessions on demand.
// This is needed to recover from backgrounding and other events that can
// invalidate compression sessions.
const FrameSenderConfig video_config_;
// Frame size of the current compression session. Can be changed by submitting
// a frame of a different size, which will cause a compression session reset.
gfx::Size frame_size_;
// Callback used to report initialization status and runtime errors.
const StatusChangeCallback status_change_cb_;
// Thread checker to enforce that this object is used on a specific thread.
base::ThreadChecker thread_checker_;
// The compression session.
base::ScopedCFTypeRef<VTCompressionSessionRef> compression_session_;
// Video frame factory tied to the encoder.
scoped_refptr<VideoFrameFactoryImpl> video_frame_factory_;
// The ID for the next frame to be emitted.
FrameId next_frame_id_;
// Force next frame to be a keyframe.
bool encode_next_frame_as_keyframe_;
// Power suspension state.
bool power_suspended_;
// NOTE: Weak pointers must be invalidated before all other member variables.
base::WeakPtrFactory<H264VideoToolboxEncoder> weak_factory_;
};
} // namespace cast
} // namespace media
#endif // MEDIA_CAST_SENDER_H264_VT_ENCODER_H_