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// Copyright (c) 2010 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.
// Implementation of Pipeline.
#include <set>
#include <string>
#include <vector>
#include "base/gtest_prod_util.h"
#include "base/message_loop.h"
#include "base/ref_counted.h"
#include "base/scoped_ptr.h"
#include "base/thread.h"
#include "base/time.h"
#include "media/base/clock_impl.h"
#include "media/base/filter_host.h"
#include "media/base/pipeline.h"
namespace media {
// PipelineImpl runs the media pipeline. Filters are created and called on the
// message loop injected into this object. PipelineImpl 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 ] [ Stopped ]
// | Start() ^
// V SetError() |
// [ InitXXX (for each filter) ] -------->[ Stopping (for each filter) ]
// | ^
// V | if Stop
// [ Seeking (for each filter) ] <--------[ Flushing (for each filter) ]
// | if Seek ^
// V |
// [ Starting (for each filter) ] |
// | |
// V Seek()/Stop() |
// [ Started ] -------------------------> [ Pausing (for each filter) ]
// | ^
// | NotifyEnded() Seek()/Stop() |
// `-------------> [ Ended ] ---------------------'
// ^ SetError()
// |
// [ Any State Other Than InitXXX ]
// 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 PipelineImpl : public Pipeline, public FilterHost {
explicit PipelineImpl(MessageLoop* message_loop);
// Pipeline implementation.
virtual bool Start(FilterFactory* filter_factory,
const std::string& uri,
PipelineCallback* start_callback);
virtual void Stop(PipelineCallback* stop_callback);
virtual void Seek(base::TimeDelta time, PipelineCallback* seek_callback);
virtual bool IsRunning() const;
virtual bool IsInitialized() const;
virtual bool IsNetworkActive() const;
virtual bool IsRendered(const std::string& major_mime_type) const;
virtual float GetPlaybackRate() const;
virtual void SetPlaybackRate(float playback_rate);
virtual float GetVolume() const;
virtual void SetVolume(float volume);
virtual base::TimeDelta GetCurrentTime() const;
virtual base::TimeDelta GetBufferedTime();
virtual base::TimeDelta GetMediaDuration() const;
virtual int64 GetBufferedBytes() const;
virtual int64 GetTotalBytes() const;
virtual void GetVideoSize(size_t* width_out, size_t* height_out) const;
virtual bool IsStreaming() const;
virtual bool IsLoaded() const;
virtual PipelineError GetError() const;
// Sets a permanent callback owned by the pipeline that will be executed when
// the media reaches the end.
virtual void SetPipelineEndedCallback(PipelineCallback* ended_callback);
// |error_callback_| will be executed upon an error in the pipeline. If
// |error_callback_| is NULL, it is ignored. The pipeline takes ownership
// of |error_callback|.
virtual void SetPipelineErrorCallback(PipelineCallback* error_callback);
// |network_callback_| will be executed when there's a network event.
virtual void SetNetworkEventCallback(PipelineCallback* network_callback);
// Pipeline states, as described above.
enum State {
virtual ~PipelineImpl();
// Reset the state of the pipeline object to the initial state. This method
// is used by the constructor, and the Stop() method.
void ResetState();
// Simple method used to make sure the pipeline is running normally.
bool IsPipelineOk();
// Helper method to tell whether we are in the state of initializing.
bool IsPipelineInitializing();
// Helper method to tell whether we are stopped or in error.
bool IsPipelineStopped();
// Helper method to tell whether we are in transition to stop state.
bool IsPipelineTearingDown();
// We could also be delayed by a transition during seek is performed.
bool IsPipelineStopPending();
// Helper method to tell whether we are in transition to seek state.
bool IsPipelineSeeking();
// Helper method to execute callback from Start() and reset
// |filter_factory_|. Called when initialization completes
// normally or when pipeline is stopped or error occurs during
// initialization.
void FinishInitialization();
// Returns true if the given state is one that transitions to a new state
// after iterating through each filter.
static bool TransientState(State state);
// Given the current state, returns the next state.
State FindNextState(State current);
// FilterHost implementation.
virtual void SetError(PipelineError error);
virtual base::TimeDelta GetTime() const;
virtual base::TimeDelta GetDuration() const;
virtual void SetTime(base::TimeDelta time);
virtual void SetDuration(base::TimeDelta duration);
virtual void SetBufferedTime(base::TimeDelta buffered_time);
virtual void SetTotalBytes(int64 total_bytes);
virtual void SetBufferedBytes(int64 buffered_bytes);
virtual void SetVideoSize(size_t width, size_t height);
virtual void SetStreaming(bool streamed);
virtual void SetLoaded(bool loaded);
virtual void SetNetworkActivity(bool network_activity);
virtual void NotifyEnded();
virtual void DisableAudioRenderer();
virtual void SetCurrentReadPosition(int64 offset);
virtual int64 GetCurrentReadPosition();
// Method called during initialization to insert a mime type into the
// |rendered_mime_types_| set.
void InsertRenderedMimeType(const std::string& major_mime_type);
// Method called during initialization to determine if we rendered anything.
bool HasRenderedMimeTypes() const;
// Callback executed by filters upon completing initialization.
void OnFilterInitialize();
// Callback executed by filters upon completing Play(), Pause(), Seek(),
// or Stop().
void OnFilterStateTransition();
// The following "task" methods correspond to the public methods, but these
// methods are run as the result of posting a task to the PipelineInternal's
// message loop.
void StartTask(FilterFactory* filter_factory,
const std::string& url,
PipelineCallback* start_callback);
// InitializeTask() performs initialization in multiple passes. It is executed
// as a result of calling Start() or InitializationComplete() that advances
// initialization to the next state. It works as a hub of state transition for
// initialization.
void InitializeTask();
// Stops and destroys all filters, placing the pipeline in the kStopped state.
void StopTask(PipelineCallback* stop_callback);
// Carries out stopping and destroying all filters, placing the pipeline in
// the kError state.
void ErrorChangedTask(PipelineError 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, PipelineCallback* seek_callback);
// Carries out handling a notification from a filter that it has ended.
void NotifyEndedTask();
// Carries out handling a notification of network event.
void NotifyNetworkEventTask();
// Carries out disabling the audio renderer.
void DisableAudioRendererTask();
// Carries out advancing to the next filter during Play()/Pause()/Seek().
void FilterStateTransitionTask();
// Carries out stopping filter threads, deleting filters, running
// appropriate callbacks, and setting the appropriate pipeline state
// depending on whether we performing Stop() or SetError().
// Called after all filters have been stopped.
void FinishDestroyingFiltersTask();
// Internal methods used in the implementation of the pipeline thread. All
// of these methods are only called on the pipeline thread.
// The following template functions make use of the fact that media filter
// derived interfaces are self-describing in the sense that they all contain
// the static method filter_type() which returns a FilterType enum that
// uniquely identifies the filter's interface. In addition, filters that are
// specific to audio or video also support a static method major_mime_type()
// which returns a string of "audio/" or "video/".
// Uses the FilterFactory to create a new filter of the Filter class, and
// initializes it using the Source object. The source may be another filter
// or it could be a string in the case of a DataSource.
// The CreateFilter() method actually does much more than simply creating the
// filter. It also creates the filter's thread and injects a FilterHost and
// MessageLoop. Finally, it calls the filter's type-specific Initialize()
// method to initialize the filter. If the required filter cannot be created,
// PIPELINE_ERROR_REQUIRED_FILTER_MISSING is raised, initialization is halted
// and this object will remain in the "Error" state.
template <class Filter, class Source>
void CreateFilter(FilterFactory* filter_factory,
Source source,
const MediaFormat& source_media_format);
// Creates a Filter and initializes it with the given |source|. If a Filter
// could not be created or an error occurred, this method returns NULL and the
// pipeline's |error_| member will contain a specific error code. Note that
// the Source could be a filter or a DemuxerStream, but it must support the
// GetMediaFormat() method.
template <class Filter, class Source>
void CreateFilter(FilterFactory* filter_factory, Source* source) {
CreateFilter<Filter, Source*>(filter_factory,
// Creates a DataSource (the first filter in a pipeline).
void CreateDataSource();
// Creates a Demuxer.
void CreateDemuxer();
// Creates a decoder of type Decoder. Returns true if the asynchronous action
// of creating decoder has started. Returns false if this method did nothing
// because the corresponding audio/video stream does not exist.
template <class Decoder>
bool CreateDecoder();
// Creates a renderer of type Renderer and connects it with Decoder. Returns
// true if the asynchronous action of creating renderer has started. Returns
// false if this method did nothing because the corresponding audio/video
// stream does not exist.
template <class Decoder, class Renderer>
bool CreateRenderer();
// Examine the list of existing filters to find one that supports the
// specified Filter interface. If one exists, the |filter_out| will contain
// the filter, |*filter_out| will be NULL.
template <class Filter>
void GetFilter(scoped_refptr<Filter>* filter_out) const;
// 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();
// Message loop used to execute pipeline tasks.
MessageLoop* message_loop_;
// Lock used to serialize access for the following data members.
mutable Lock lock_;
// Whether or not the pipeline is running.
bool running_;
// Whether or not the pipeline is in transition for a seek operation.
bool seek_pending_;
// Whether or not the pipeline is pending a stop operation.
bool stop_pending_;
// Whether or not the pipeline is perform a stop operation.
bool tearing_down_;
// Duration of the media in microseconds. Set by filters.
base::TimeDelta duration_;
// Amount of available buffered data in microseconds. Set by filters.
base::TimeDelta buffered_time_;
// Amount of available buffered data. Set by filters.
int64 buffered_bytes_;
// Total size of the media. Set by filters.
int64 total_bytes_;
// Video width and height. Set by filters.
size_t video_width_;
size_t video_height_;
// Sets by the filters to indicate whether the data source is a streaming
// source.
bool streaming_;
// Sets by the filters to indicate whether the data source is a fully
// loaded source.
bool loaded_;
// Sets by the filters to indicate whether network is active.
bool network_activity_;
// Current volume level (from 0.0f to 1.0f). This value is set immediately
// via SetVolume() and a task is dispatched on the message loop 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 message loop to notify
// the filters.
float playback_rate_;
// Reference clock. Keeps track of current playback time. Uses system
// clock and linear interpolation, but can have its time manually set
// by filters.
ClockImpl 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.
PipelineError error_;
// Vector of major mime types that have been rendered by this pipeline.
typedef std::set<std::string> RenderedMimeTypesSet;
RenderedMimeTypesSet rendered_mime_types_;
// The following data members are only accessed by tasks posted to
// |message_loop_|.
// Member that tracks the current state.
State state_;
// For kPausing, kSeeking and kStarting, we need to track how many filters
// have completed transitioning to the destination state. When
// |remaining_transitions_| reaches 0 the pipeline can transition out
// of the current state.
size_t remaining_transitions_;
// For kSeeking we need to remember where we're seeking between filter
// replies.
base::TimeDelta seek_timestamp_;
// For GetCurrentBytes()/SetCurrentBytes() we need to know what byte we are
// currently reading.
int64 current_bytes_;
// Set to true in DisableAudioRendererTask().
bool audio_disabled_;
// Keep track of the maximum buffered position so the buffering appears
// smooth.
// TODO(vrk): This is a hack.
base::TimeDelta max_buffered_time_;
// Filter factory as passed in by Start().
scoped_refptr<FilterFactory> filter_factory_;
// URL for the data source as passed in by Start().
std::string url_;
// Callbacks for various pipeline operations.
scoped_ptr<PipelineCallback> seek_callback_;
scoped_ptr<PipelineCallback> stop_callback_;
scoped_ptr<PipelineCallback> ended_callback_;
scoped_ptr<PipelineCallback> error_callback_;
scoped_ptr<PipelineCallback> network_callback_;
// Vector of our filters and map maintaining the relationship between the
// FilterType and the filter itself.
typedef std::vector<scoped_refptr<MediaFilter> > FilterVector;
FilterVector filters_;
typedef std::map<FilterType, scoped_refptr<MediaFilter> > FilterTypeMap;
FilterTypeMap filter_types_;
// Vector of threads owned by the pipeline and being used by filters.
typedef std::vector<base::Thread*> FilterThreadVector;
FilterThreadVector filter_threads_;
FRIEND_TEST_ALL_PREFIXES(PipelineImplTest, GetBufferedTime);
} // namespace media