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// 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_BASE_PIPELINE_H_
#define MEDIA_BASE_PIPELINE_H_
#include "base/gtest_prod_util.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/synchronization/lock.h"
#include "base/threading/thread_checker.h"
#include "base/time/default_tick_clock.h"
#include "media/base/buffering_state.h"
#include "media/base/cdm_context.h"
#include "media/base/demuxer.h"
#include "media/base/media_export.h"
#include "media/base/pipeline_status.h"
#include "media/base/ranges.h"
#include "media/base/serial_runner.h"
#include "media/base/text_track.h"
#include "media/base/video_rotation.h"
#include "ui/gfx/size.h"
namespace base {
class SingleThreadTaskRunner;
class TimeDelta;
}
namespace media {
class MediaLog;
class Renderer;
class TextRenderer;
class TextTrackConfig;
class TimeDeltaInterpolator;
class VideoFrame;
// Metadata describing a pipeline once it has been initialized.
struct PipelineMetadata {
PipelineMetadata()
: has_audio(false), has_video(false), video_rotation(VIDEO_ROTATION_0) {}
bool has_audio;
bool has_video;
gfx::Size natural_size;
VideoRotation video_rotation;
base::Time timeline_offset;
};
typedef base::Callback<void(PipelineMetadata)> PipelineMetadataCB;
// Pipeline runs the media pipeline. Filters are created and called on the
// task runner injected into this object. Pipeline works like a state
// machine to perform asynchronous initialization, pausing, seeking and playing.
//
// Here's a state diagram that describes the lifetime of this object.
//
// [ *Created ] [ Any State ]
// | Start() | Stop() / SetError()
// V V
// [ InitXXX (for each filter) ] [ Stopping ]
// | |
// V V
// [ Playing ] <-- [ Seeking ] [ Stopped ]
// | ^
// `---------------'
// Seek()
//
// Initialization is a series of state transitions from "Created" through each
// filter initialization state. When all filter initialization states have
// completed, we are implicitly in a "Paused" state. At that point we simulate
// a Seek() to the beginning of the media to give filters a chance to preroll.
// From then on the normal Seek() transitions are carried out and we start
// playing the media.
//
// If any error ever happens, this object will transition to the "Error" state
// from any state. If Stop() is ever called, this object will transition to
// "Stopped" state.
class MEDIA_EXPORT Pipeline : public DemuxerHost {
public:
// Used to paint VideoFrame.
typedef base::Callback<void(const scoped_refptr<VideoFrame>&)> PaintCB;
// Constructs a media pipeline that will execute on |task_runner|.
Pipeline(const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
MediaLog* media_log);
~Pipeline() override;
// Build a pipeline to using the given |demuxer| and |renderer| to construct
// a filter chain, executing |seek_cb| when the initial seek has completed.
//
// The following permanent callbacks will be executed as follows up until
// Stop() has completed:
// |ended_cb| will be executed whenever the media reaches the end.
// |error_cb| will be executed whenever an error occurs but hasn't been
// reported already through another callback.
// |metadata_cb| will be executed when the content duration, container video
// size, start time, and whether the content has audio and/or
// video in supported formats are known.
// |buffering_state_cb| will be executed whenever there are changes in the
// overall buffering state of the pipeline.
// |paint_cb| will be executed whenever there is a VideoFrame to be painted.
// It's safe to call this callback from any thread.
// |duration_change_cb| optional callback that will be executed whenever the
// presentation duration changes.
// |add_text_track_cb| will be executed whenever a text track is added.
// It is an error to call this method after the pipeline has already started.
void Start(Demuxer* demuxer,
scoped_ptr<Renderer> renderer,
const base::Closure& ended_cb,
const PipelineStatusCB& error_cb,
const PipelineStatusCB& seek_cb,
const PipelineMetadataCB& metadata_cb,
const BufferingStateCB& buffering_state_cb,
const PaintCB& paint_cb,
const base::Closure& duration_change_cb,
const AddTextTrackCB& add_text_track_cb);
// Asynchronously stops the pipeline, executing |stop_cb| when the pipeline
// teardown has completed.
//
// Stop() must complete before destroying the pipeline. It it permissible to
// call Stop() at any point during the lifetime of the pipeline.
//
// It is safe to delete the pipeline during the execution of |stop_cb|.
void Stop(const base::Closure& stop_cb);
// Attempt to seek to the position specified by time. |seek_cb| will be
// executed when the all filters in the pipeline have processed the seek.
//
// Clients are expected to call GetMediaTime() to check whether the seek
// succeeded.
//
// It is an error to call this method if the pipeline has not started.
void Seek(base::TimeDelta time, const PipelineStatusCB& seek_cb);
// Returns true if the pipeline has been started via Start(). If IsRunning()
// returns true, it is expected that Stop() will be called before destroying
// the pipeline.
bool IsRunning() const;
// Gets the current playback rate of the pipeline. When the pipeline is
// started, the playback rate will be 0.0f. A rate of 1.0f indicates
// that the pipeline is rendering the media at the standard rate. Valid
// values for playback rate are >= 0.0f.
float GetPlaybackRate() const;
// Attempt to adjust the playback rate. Setting a playback rate of 0.0f pauses
// all rendering of the media. A rate of 1.0f indicates a normal playback
// rate. Values for the playback rate must be greater than or equal to 0.0f.
//
// TODO(scherkus): What about maximum rate? Does HTML5 specify a max?
void SetPlaybackRate(float playback_rate);
// Gets the current volume setting being used by the audio renderer. When
// the pipeline is started, this value will be 1.0f. Valid values range
// from 0.0f to 1.0f.
float GetVolume() const;
// Attempt to set the volume of the audio renderer. Valid values for volume
// range from 0.0f (muted) to 1.0f (full volume). This value affects all
// channels proportionately for multi-channel audio streams.
void SetVolume(float volume);
// Returns the current media playback time, which progresses from 0 until
// GetMediaDuration().
base::TimeDelta GetMediaTime() const;
// Get approximate time ranges of buffered media.
Ranges<base::TimeDelta> GetBufferedTimeRanges() const;
// Get the duration of the media in microseconds. If the duration has not
// been determined yet, then returns 0.
base::TimeDelta GetMediaDuration() const;
// Return true if loading progress has been made since the last time this
// method was called.
bool DidLoadingProgress();
// Gets the current pipeline statistics.
PipelineStatistics GetStatistics() const;
void SetCdm(CdmContext* cdm_context, const CdmAttachedCB& cdm_attached_cb);
void SetErrorForTesting(PipelineStatus status);
bool HasWeakPtrsForTesting() const;
private:
FRIEND_TEST_ALL_PREFIXES(PipelineTest, GetBufferedTimeRanges);
FRIEND_TEST_ALL_PREFIXES(PipelineTest, EndedCallback);
FRIEND_TEST_ALL_PREFIXES(PipelineTest, AudioStreamShorterThanVideo);
friend class MediaLog;
// Pipeline states, as described above.
enum State {
kCreated,
kInitDemuxer,
kInitRenderer,
kSeeking,
kPlaying,
kStopping,
kStopped,
};
// Updates |state_|. All state transitions should use this call.
void SetState(State next_state);
static const char* GetStateString(State state);
State GetNextState() const;
// Helper method that runs & resets |seek_cb_| and resets |seek_timestamp_|
// and |seek_pending_|.
void FinishSeek();
// DemuxerHost implementaion.
void AddBufferedTimeRange(base::TimeDelta start,
base::TimeDelta end) override;
void SetDuration(base::TimeDelta duration) override;
void OnDemuxerError(PipelineStatus error) override;
void AddTextStream(DemuxerStream* text_stream,
const TextTrackConfig& config) override;
void RemoveTextStream(DemuxerStream* text_stream) override;
// Callback executed when a rendering error happened, initiating the teardown
// sequence.
void OnError(PipelineStatus error);
// Callback executed by filters to update statistics.
void OnUpdateStatistics(const PipelineStatistics& stats);
// The following "task" methods correspond to the public methods, but these
// methods are run as the result of posting a task to the Pipeline's
// task runner.
void StartTask();
// Stops and destroys all filters, placing the pipeline in the kStopped state.
void StopTask(const base::Closure& stop_cb);
// Carries out stopping and destroying all filters, placing the pipeline in
// the kStopped state.
void ErrorChangedTask(PipelineStatus error);
// Carries out notifying filters that the playback rate has changed.
void PlaybackRateChangedTask(float playback_rate);
// Carries out notifying filters that the volume has changed.
void VolumeChangedTask(float volume);
// Carries out notifying filters that we are seeking to a new timestamp.
void SeekTask(base::TimeDelta time, const PipelineStatusCB& seek_cb);
// Carries out setting the |cdm_context| in |renderer_|, and then fires
// |cdm_attached_cb| with the result. If |renderer_| is null,
// |cdm_attached_cb| will be fired immediately with true, and |cdm_context|
// will be set in |renderer_| later when |renderer_| is created.
void SetCdmTask(CdmContext* cdm_context,
const CdmAttachedCB& cdm_attached_cb);
// Callbacks executed when a renderer has ended.
void OnRendererEnded();
void OnTextRendererEnded();
void RunEndedCallbackIfNeeded();
scoped_ptr<TextRenderer> CreateTextRenderer();
// Carries out adding a new text stream to the text renderer.
void AddTextStreamTask(DemuxerStream* text_stream,
const TextTrackConfig& config);
// Carries out removing a text stream from the text renderer.
void RemoveTextStreamTask(DemuxerStream* text_stream);
// Callbacks executed when a text track is added.
void OnAddTextTrack(const TextTrackConfig& config,
const AddTextTrackDoneCB& done_cb);
// Kicks off initialization for each media object, executing |done_cb| with
// the result when completed.
void InitializeDemuxer(const PipelineStatusCB& done_cb);
void InitializeRenderer(const base::Closure& done_cb);
void OnStateTransition(PipelineStatus status);
void StateTransitionTask(PipelineStatus status);
// Initiates an asynchronous pause-flush-seek-preroll call sequence
// executing |done_cb| with the final status when completed.
void DoSeek(base::TimeDelta seek_timestamp, const PipelineStatusCB& done_cb);
// Initiates an asynchronous pause-flush-stop call sequence executing
// |done_cb| when completed.
void DoStop(const PipelineStatusCB& done_cb);
void OnStopCompleted(PipelineStatus status);
void ReportMetadata();
void BufferingStateChanged(BufferingState new_buffering_state);
// Task runner used to execute pipeline tasks.
scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
// MediaLog to which to log events.
scoped_refptr<MediaLog> media_log_;
// Lock used to serialize access for the following data members.
mutable base::Lock lock_;
// Whether or not the pipeline is running.
bool running_;
// Amount of available buffered data as reported by |demuxer_|.
Ranges<base::TimeDelta> buffered_time_ranges_;
// True when AddBufferedTimeRange() has been called more recently than
// DidLoadingProgress().
bool did_loading_progress_;
// Current volume level (from 0.0f to 1.0f). This value is set immediately
// via SetVolume() and a task is dispatched on the task runner to notify the
// filters.
float volume_;
// Current playback rate (>= 0.0f). This value is set immediately via
// SetPlaybackRate() and a task is dispatched on the task runner to notify
// the filters.
float playback_rate_;
// Current duration as reported by |demuxer_|.
base::TimeDelta duration_;
// Status of the pipeline. Initialized to PIPELINE_OK which indicates that
// the pipeline is operating correctly. Any other value indicates that the
// pipeline is stopped or is stopping. Clients can call the Stop() method to
// reset the pipeline state, and restore this to PIPELINE_OK.
PipelineStatus status_;
// The following data members are only accessed by tasks posted to
// |task_runner_|.
bool is_initialized_;
// Member that tracks the current state.
State state_;
// The timestamp to start playback from after starting/seeking has completed.
base::TimeDelta start_timestamp_;
// Whether we've received the audio/video/text ended events.
bool renderer_ended_;
bool text_renderer_ended_;
// Temporary callback used for Start() and Seek().
PipelineStatusCB seek_cb_;
// Temporary callback used for Stop().
base::Closure stop_cb_;
// Permanent callbacks passed in via Start().
base::Closure ended_cb_;
PipelineStatusCB error_cb_;
PipelineMetadataCB metadata_cb_;
BufferingStateCB buffering_state_cb_;
PaintCB paint_cb_;
base::Closure duration_change_cb_;
AddTextTrackCB add_text_track_cb_;
// Holds the initialized demuxer. Used for seeking. Owned by client.
Demuxer* demuxer_;
// Holds the initialized renderers. Used for setting the volume,
// playback rate, and determining when playback has finished.
scoped_ptr<Renderer> renderer_;
scoped_ptr<TextRenderer> text_renderer_;
PipelineStatistics statistics_;
scoped_ptr<SerialRunner> pending_callbacks_;
// CdmContext to be used to decrypt (and decode) encrypted stream in this
// pipeline. Non-null only when SetCdm() is called and the pipeline has not
// been started. Then during Start(), this value will be set on |renderer_|.
CdmContext* pending_cdm_context_;
base::ThreadChecker thread_checker_;
// NOTE: Weak pointers must be invalidated before all other member variables.
base::WeakPtrFactory<Pipeline> weak_factory_;
DISALLOW_COPY_AND_ASSIGN(Pipeline);
};
} // namespace media
#endif // MEDIA_BASE_PIPELINE_H_