// 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 <string>
#include "base/gtest_prod_util.h"
#include "base/synchronization/condition_variable.h"
#include "base/synchronization/lock.h"
#include "base/threading/thread_checker.h"
#include "base/time/default_tick_clock.h"
#include "media/base/audio_renderer.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 "ui/gfx/size.h"
namespace base {
class SingleThreadTaskRunner;
class TimeDelta;
}
namespace media {
class Clock;
class FilterCollection;
class MediaLog;
class TextRenderer;
class TextTrackConfig;
class VideoRenderer;
// Metadata describing a pipeline once it has been initialized.
struct PipelineMetadata {
PipelineMetadata() : has_audio(false), has_video(false) {}
bool has_audio;
bool has_video;
gfx::Size natural_size;
};
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
// [ InitPreroll ] [ Stopped ]
// |
// V
// [ Starting ] <-- [ Seeking ]
// | ^
// V |
// [ Started ] ----------'
// 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 DataSourceHost, public DemuxerHost {
public:
// Constructs a media pipeline that will execute on |task_runner|.
Pipeline(const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
MediaLog* media_log);
virtual ~Pipeline();
// Build a pipeline to using the given filter collection to construct a filter
// chain, executing |seek_cb| when the initial seek/preroll has completed.
//
// |filter_collection| must be a complete collection containing a demuxer,
// audio/video decoders, and audio/video renderers. Failing to do so will
// result in a crash.
//
// 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.
// |preroll_completed_cb| will be executed when all renderers have buffered
// enough data to satisfy preroll and are ready to
// start playback.
// |duration_change_cb| optional callback that will be executed whenever the
// presentation duration changes.
// It is an error to call this method after the pipeline has already started.
void Start(scoped_ptr<FilterCollection> filter_collection,
const base::Closure& ended_cb,
const PipelineStatusCB& error_cb,
const PipelineStatusCB& seek_cb,
const PipelineMetadataCB& metadata_cb,
const base::Closure& preroll_completed_cb,
const base::Closure& duration_change_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();
// Get the duration of the media in microseconds. If the duration has not
// been determined yet, then returns 0.
base::TimeDelta GetMediaDuration() const;
// Get the total size of the media file. If the size has not yet been
// determined or can not be determined, this value is 0.
int64 GetTotalBytes() const;
// Return true if loading progress has been made since the last time this
// method was called.
bool DidLoadingProgress() const;
// Gets the current pipeline statistics.
PipelineStatistics GetStatistics() const;
void SetClockForTesting(Clock* clock);
void SetErrorForTesting(PipelineStatus status);
private:
FRIEND_TEST_ALL_PREFIXES(PipelineTest, GetBufferedTimeRanges);
FRIEND_TEST_ALL_PREFIXES(PipelineTest, DisableAudioRenderer);
FRIEND_TEST_ALL_PREFIXES(PipelineTest, DisableAudioRendererDuringInit);
FRIEND_TEST_ALL_PREFIXES(PipelineTest, EndedCallback);
FRIEND_TEST_ALL_PREFIXES(PipelineTest, AudioStreamShorterThanVideo);
friend class MediaLog;
// Pipeline states, as described above.
enum State {
kCreated,
kInitDemuxer,
kInitAudioRenderer,
kInitVideoRenderer,
kInitPrerolling,
kSeeking,
kStarting,
kStarted,
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();
// DataSourceHost (by way of DemuxerHost) implementation.
virtual void SetTotalBytes(int64 total_bytes) OVERRIDE;
virtual void AddBufferedByteRange(int64 start, int64 end) OVERRIDE;
virtual void AddBufferedTimeRange(base::TimeDelta start,
base::TimeDelta end) OVERRIDE;
// DemuxerHost implementaion.
virtual void SetDuration(base::TimeDelta duration) OVERRIDE;
virtual void OnDemuxerError(PipelineStatus error) OVERRIDE;
virtual void AddTextStream(DemuxerStream* text_stream,
const TextTrackConfig& config) OVERRIDE;
virtual void RemoveTextStream(DemuxerStream* text_stream) OVERRIDE;
// Initiates teardown sequence in response to a runtime error.
//
// Safe to call from any thread.
void SetError(PipelineStatus error);
// Callbacks executed when a renderer has ended.
void OnAudioRendererEnded();
void OnVideoRendererEnded();
void OnTextRendererEnded();
// Callback executed by filters to update statistics.
void OnUpdateStatistics(const PipelineStatistics& stats);
// Callback executed by audio renderer when it has been disabled.
void OnAudioDisabled();
// Callback executed by audio renderer to update clock time.
void OnAudioTimeUpdate(base::TimeDelta time, base::TimeDelta max_time);
// Callback executed by video renderer to update clock time.
void OnVideoTimeUpdate(base::TimeDelta max_time);
// 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);
// Handles audio/video/text ended logic and running |ended_cb_|.
void DoAudioRendererEnded();
void DoVideoRendererEnded();
void DoTextRendererEnded();
void RunEndedCallbackIfNeeded();
// Carries out disabling the audio renderer.
void AudioDisabledTask();
// 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);
// Kicks off initialization for each media object, executing |done_cb| with
// the result when completed.
void InitializeDemuxer(const PipelineStatusCB& done_cb);
void InitializeAudioRenderer(const PipelineStatusCB& done_cb);
void InitializeVideoRenderer(const PipelineStatusCB& done_cb);
// Kicks off destroying filters. Called by StopTask() and ErrorChangedTask().
// When we start to tear down the pipeline, we will consider two cases:
// 1. when pipeline has not been initialized, we will transit to stopping
// state first.
// 2. when pipeline has been initialized, we will first transit to pausing
// => flushing => stopping => stopped state.
// This will remove the race condition during stop between filters.
void TearDownPipeline();
// Compute the time corresponding to a byte offset.
base::TimeDelta TimeForByteOffset_Locked(int64 byte_offset) const;
void OnStateTransition(PipelineStatus status);
void StateTransitionTask(PipelineStatus status);
// Initiates an asynchronous preroll call sequence executing |done_cb|
// with the final status when completed.
void DoInitialPreroll(const PipelineStatusCB& done_cb);
// Initiates an asynchronous pause-flush-seek-preroll call sequence
// executing |done_cb| with the final status when completed.
//
// TODO(scherkus): Prerolling should be separate from seeking so we can report
// finer grained ready states (HAVE_CURRENT_DATA vs. HAVE_FUTURE_DATA)
// indepentent from seeking.
void DoSeek(base::TimeDelta seek_timestamp, const PipelineStatusCB& done_cb);
// Updates playback rate and volume and initiates an asynchronous play call
// sequence executing |done_cb| with the final status when completed.
void DoPlay(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 OnAudioUnderflow();
void StartClockIfWaitingForTimeUpdate_Locked();
// 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. Set by filters.
Ranges<int64> buffered_byte_ranges_;
Ranges<base::TimeDelta> buffered_time_ranges_;
// True when AddBufferedByteRange() has been called more recently than
// DidLoadingProgress().
mutable bool did_loading_progress_;
// Total size of the media. Set by filters.
int64 total_bytes_;
// 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_;
// base::TickClock used by |clock_|.
base::DefaultTickClock default_tick_clock_;
// Reference clock. Keeps track of current playback time. Uses system
// clock and linear interpolation, but can have its time manually set
// by filters.
scoped_ptr<Clock> clock_;
// If this value is set to true, then |clock_| is paused and we are waiting
// for an update of the clock greater than or equal to the elapsed time to
// start the clock.
bool waiting_for_clock_update_;
// 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_|.
// Member that tracks the current state.
State state_;
// Whether we've received the audio/video/text ended events.
bool audio_ended_;
bool video_ended_;
bool text_ended_;
// Set to true in DisableAudioRendererTask().
bool audio_disabled_;
// 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_;
base::Closure preroll_completed_cb_;
base::Closure duration_change_cb_;
// Contains the demuxer and renderers to use when initializing.
scoped_ptr<FilterCollection> filter_collection_;
// 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<AudioRenderer> audio_renderer_;
scoped_ptr<VideoRenderer> video_renderer_;
scoped_ptr<TextRenderer> text_renderer_;
PipelineStatistics statistics_;
// Time of pipeline creation; is non-zero only until the pipeline first
// reaches "kStarted", at which point it is used & zeroed out.
base::TimeTicks creation_time_;
scoped_ptr<SerialRunner> pending_callbacks_;
base::ThreadChecker thread_checker_;
DISALLOW_COPY_AND_ASSIGN(Pipeline);
};
} // namespace media
#endif // MEDIA_BASE_PIPELINE_H_