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// Copyright 2013 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_RENDERERS_VIDEO_RENDERER_IMPL_H_
#define MEDIA_RENDERERS_VIDEO_RENDERER_IMPL_H_
#include <stddef.h>
#include <stdint.h>
#include <memory>
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/synchronization/condition_variable.h"
#include "base/synchronization/lock.h"
#include "base/timer/timer.h"
#include "media/base/decryptor.h"
#include "media/base/demuxer_stream.h"
#include "media/base/media_log.h"
#include "media/base/pipeline_status.h"
#include "media/base/video_decoder.h"
#include "media/base/video_decoder_config.h"
#include "media/base/video_frame.h"
#include "media/base/video_renderer.h"
#include "media/base/video_renderer_sink.h"
#include "media/filters/decoder_stream.h"
#include "media/filters/video_renderer_algorithm.h"
#include "media/renderers/default_renderer_factory.h"
#include "media/video/gpu_memory_buffer_video_frame_pool.h"
namespace base {
class SingleThreadTaskRunner;
class TickClock;
} // namespace base
namespace media {
// VideoRendererImpl handles reading from a VideoFrameStream storing the
// results in a queue of decoded frames and executing a callback when a frame is
// ready for rendering.
class MEDIA_EXPORT VideoRendererImpl
: public VideoRenderer,
public VideoRendererSink::RenderCallback {
public:
// |decoders| contains the VideoDecoders to use when initializing.
//
// Implementors should avoid doing any sort of heavy work in this method and
// instead post a task to a common/worker thread to handle rendering. Slowing
// down the video thread may result in losing synchronization with audio.
//
// Setting |drop_frames_| to true causes the renderer to drop expired frames.
VideoRendererImpl(
const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner,
VideoRendererSink* sink,
const CreateVideoDecodersCB& create_video_decoders_cb,
bool drop_frames,
MediaLog* media_log,
std::unique_ptr<GpuMemoryBufferVideoFramePool> gmb_pool);
~VideoRendererImpl() override;
// VideoRenderer implementation.
void Initialize(DemuxerStream* stream,
CdmContext* cdm_context,
RendererClient* client,
const TimeSource::WallClockTimeCB& wall_clock_time_cb,
const PipelineStatusCB& init_cb) override;
void Flush(const base::Closure& callback) override;
void StartPlayingFrom(base::TimeDelta timestamp) override;
void OnTimeProgressing() override;
void OnTimeStopped() override;
void SetTickClockForTesting(const base::TickClock* tick_clock);
size_t frames_queued_for_testing() const {
return algorithm_->frames_queued();
}
size_t effective_frames_queued_for_testing() const {
return algorithm_->effective_frames_queued();
}
// VideoRendererSink::RenderCallback implementation.
scoped_refptr<VideoFrame> Render(base::TimeTicks deadline_min,
base::TimeTicks deadline_max,
bool background_rendering) override;
void OnFrameDropped() override;
private:
// Callback for |video_frame_stream_| initialization.
void OnVideoFrameStreamInitialized(bool success);
// Functions to notify certain events to the RendererClient.
void OnPlaybackError(PipelineStatus error);
void OnPlaybackEnded();
void OnStatisticsUpdate(const PipelineStatistics& stats);
void OnBufferingStateChange(BufferingState state);
void OnWaitingForDecryptionKey();
// Called by the VideoFrameStream when a config change occurs. Will notify
// RenderClient of the new config.
void OnConfigChange(const VideoDecoderConfig& config);
// Callback for |video_frame_stream_| to deliver decoded video frames and
// report video decoding status.
void FrameReady(VideoFrameStream::Status status,
const scoped_refptr<VideoFrame>& frame);
// Helper method for enqueueing a frame to |alogorithm_|.
void AddReadyFrame_Locked(const scoped_refptr<VideoFrame>& frame);
// Helper method that schedules an asynchronous read from the
// |video_frame_stream_| as long as there isn't a pending read and we have
// capacity.
void AttemptRead_Locked();
// Called when VideoFrameStream::Reset() completes.
void OnVideoFrameStreamResetDone();
// Returns true if the renderer has enough data for playback purposes.
// Note that having enough data may be due to reaching end of stream.
bool HaveEnoughData_Locked() const;
void TransitionToHaveEnough_Locked();
void TransitionToHaveNothing();
void TransitionToHaveNothing_Locked();
// Runs |statistics_cb_| with |frames_decoded_| and |frames_dropped_|, resets
// them to 0.
void UpdateStats_Locked();
// Returns true if there is no more room for additional buffered frames.
bool HaveReachedBufferingCap() const;
// Starts or stops |sink_| respectively. Do not call while |lock_| is held.
void StartSink();
void StopSink();
// Fires |ended_cb_| if there are no remaining usable frames and
// |received_end_of_stream_| is true. Sets |rendered_end_of_stream_| if it
// does so.
//
// When called from the media thread, |time_progressing| should reflect the
// value of |time_progressing_|. When called from Render() on the sink
// callback thread, |time_progressing| must be true since Render() could not
// have been called otherwise.
void MaybeFireEndedCallback_Locked(bool time_progressing);
// Helper method for converting a single media timestamp to wall clock time.
base::TimeTicks ConvertMediaTimestamp(base::TimeDelta media_timestamp);
base::TimeTicks GetCurrentMediaTimeAsWallClockTime();
// Helper method for checking if a frame timestamp plus the frame's expected
// duration is before |start_timestamp_|.
bool IsBeforeStartTime(base::TimeDelta timestamp);
// Attempts to remove frames which are no longer effective for rendering when
// |buffering_state_| == BUFFERING_HAVE_NOTHING or |was_background_rendering_|
// is true. If the current media time as provided by |wall_clock_time_cb_| is
// null, no frame expiration will be done.
//
// When background rendering the method will expire all frames before the
// current wall clock time since it's expected that there will be long delays
// between each Render() call in this state.
//
// When in the underflow state the method will first attempt to remove expired
// frames before the current media time plus duration. If |sink_started_| is
// true, nothing more can be done. However, if false, and there are still no
// effective frames in the queue, the entire frame queue will be released to
// avoid any stalling.
void RemoveFramesForUnderflowOrBackgroundRendering();
// Notifies |client_| in the event of frame size or opacity changes. Must be
// called on |task_runner_|.
void CheckForMetadataChanges(VideoPixelFormat pixel_format,
const gfx::Size& natural_size);
// Both calls AttemptRead_Locked() and CheckForMetadataChanges(). Must be
// called on |task_runner_|.
void AttemptReadAndCheckForMetadataChanges(VideoPixelFormat pixel_format,
const gfx::Size& natural_size);
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
// Sink which calls into VideoRendererImpl via Render() for video frames. Do
// not call any methods on the sink while |lock_| is held or the two threads
// might deadlock. Do not call Start() or Stop() on the sink directly, use
// StartSink() and StopSink() to ensure background rendering is started. Only
// access these values on |task_runner_|.
VideoRendererSink* const sink_;
bool sink_started_;
// Stores the last decoder config that was passed to
// RendererClient::OnVideoConfigChange. Used to prevent signaling config
// to the upper layers when when the new config is the same.
VideoDecoderConfig current_decoder_config_;
// Used for accessing data members.
base::Lock lock_;
RendererClient* client_;
// Pool of GpuMemoryBuffers and resources used to create hardware frames.
// Ensure this is destructed after |algorithm_| for optimal memory release
// when a frames are still held by the compositor. Must be destructed after
// |video_frame_stream_| since it holds a callback to the pool.
std::unique_ptr<GpuMemoryBufferVideoFramePool> gpu_memory_buffer_pool_;
// Provides video frames to VideoRendererImpl.
std::unique_ptr<VideoFrameStream> video_frame_stream_;
MediaLog* media_log_;
// Flag indicating low-delay mode.
bool low_delay_;
// Keeps track of whether we received the end of stream buffer and finished
// rendering.
bool received_end_of_stream_;
bool rendered_end_of_stream_;
// Important detail: being in kPlaying doesn't imply that video is being
// rendered. Rather, it means that the renderer is ready to go. The actual
// rendering of video is controlled by time advancing via |get_time_cb_|.
// Video renderer can be reinitialized completely by calling Initialize again
// when it is in a kFlushed state with video sink stopped.
//
// kUninitialized
// +------> | Initialize()
// | |
// | V
// | kInitializing
// | | Decoders initialized
// | |
// | V Decoders reset
// ---- kFlushed <------------------ kFlushing
// | StartPlayingFrom() ^
// | |
// | | Flush()
// `---------> kPlaying --------'
enum State { kUninitialized, kInitializing, kFlushing, kFlushed, kPlaying };
State state_;
// TODO(servolk): Consider using DecoderFactory here instead of the
// CreateVideoDecodersCB.
CreateVideoDecodersCB create_video_decoders_cb_;
// Keep track of the outstanding read on the VideoFrameStream. Flushing can
// only complete once the read has completed.
bool pending_read_;
bool drop_frames_;
BufferingState buffering_state_;
// Playback operation callbacks.
PipelineStatusCB init_cb_;
base::Closure flush_cb_;
TimeSource::WallClockTimeCB wall_clock_time_cb_;
base::TimeDelta start_timestamp_;
// Keeps track of the number of frames decoded and dropped since the
// last call to |statistics_cb_|. These must be accessed under lock.
PipelineStatistics stats_;
const base::TickClock* tick_clock_;
// Algorithm for selecting which frame to render; manages frames and all
// timing related information. Ensure this is destructed before
// |gpu_memory_buffer_pool_| for optimal memory release when a frames are
// still held by the compositor.
std::unique_ptr<VideoRendererAlgorithm> algorithm_;
// Indicates that Render() was called with |background_rendering| set to true,
// so we've entered a background rendering mode where dropped frames are not
// counted. Must be accessed under |lock_| once |sink_| is started.
bool was_background_rendering_;
// Indicates whether or not media time is currently progressing or not. Must
// only be accessed from |task_runner_|.
bool time_progressing_;
// Indicates if a frame has been processed by CheckForMetadataChanges().
bool have_renderered_frames_;
// Tracks last frame properties to detect and notify client of any changes.
gfx::Size last_frame_natural_size_;
bool last_frame_opaque_;
// Indicates if we've painted the first valid frame after StartPlayingFrom().
bool painted_first_frame_;
// Current minimum and maximum for buffered frames. |min_buffered_frames_| is
// the number of frames required to transition from BUFFERING_HAVE_NOTHING to
// BUFFERING_HAVE_ENOUGH.
size_t min_buffered_frames_;
// Last Render() and last FrameReady() times respectively. Used to avoid
// triggering underflow when background rendering.
base::TimeTicks last_render_time_;
base::TimeTicks last_frame_ready_time_;
// NOTE: Weak pointers must be invalidated before all other member variables.
base::WeakPtrFactory<VideoRendererImpl> weak_factory_;
// Weak factory used to invalidate certain queued callbacks on reset().
// This is useful when doing video frame copies asynchronously since we
// want to discard video frames that might be received after the stream has
// been reset.
base::WeakPtrFactory<VideoRendererImpl> frame_callback_weak_factory_;
DISALLOW_COPY_AND_ASSIGN(VideoRendererImpl);
};
} // namespace media
#endif // MEDIA_RENDERERS_VIDEO_RENDERER_IMPL_H_