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// Copyright (c) 2006-2008 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.
// The pipeline is the public API clients use for playing back media. Clients
// provide a filter factory containing the filters they want the pipeline to
// use to render media.
//
// Playback controls (play, pause, seek) are asynchronous and clients are
// notified via callbacks.
#ifndef MEDIA_BASE_PIPELINE_H_
#define MEDIA_BASE_PIPELINE_H_
#include "base/task.h"
namespace media {
class FilterFactoryInterface;
enum PipelineState {
PS_UNINITIALIZED,
PS_PLAY,
PS_PAUSE,
PS_SEEK,
PS_SHUTDOWN
};
class Pipeline : public base::RefCountedThreadSafe<Pipeline> {
public:
// Build a pipeline to render the given URI using the given filter factory to
// construct a filter chain. Returns true if successful, false otherwise
// (i.e., pipeline already initialized).
//
// This method is asynchronous and will execute a state change callback when
// completed.
virtual bool Initialize(FilterFactoryInterface* filter_factory,
const std::string& uri) = 0;
// Attempt to play the media. Returns true if successful, false otherwise
// (i.e., pipeline is unititalized).
//
// This method is asynchronous and will execute a state change callback when
// completed.
virtual bool Play() = 0;
// Attempt to pause the media. Returns true if successful, false otherwise
// (i.e., pipeline is unititalized). Pause() is not a toggle and should not
// resume playback if already paused.
//
// This method is asynchronous and will execute a state change callback when
// completed.
virtual bool Pause() = 0;
// Attempt to seek to the position in microseconds. Returns true if
// successful, false otherwise. Playback is paused after the seek completes.
//
// This method is asynchronous and will execute a state change callback when
// completed.
virtual bool Seek(int64 seek_position) = 0;
// Shutdown the pipeline and destroy the filter chain.
virtual void Shutdown() = 0;
// Returns the current playback position in microseconds.
virtual int64 GetTime() const = 0;
// Returns the media duration in microseconds. Returns zero if the duration
// is not known (i.e., streaming media).
virtual int64 GetDuration() const = 0;
// Set a callback to receive state change notifications. This callback is
// executed only after the state transition has been successfully carried out.
// For example, calling Play() will only execute a callback with PS_PLAY
// some time in the future.
virtual void SetStateChangedCallback(
Callback1<PipelineState>::Type* callback) = 0;
// Set a callback to receive time change notifications.
virtual void SetTimeChangedCallback(Callback1<int64>::Type* callback) = 0;
protected:
friend class base::RefCountedThreadSafe<Pipeline>;
virtual ~Pipeline() {}
};
} // namespace media
#endif // MEDIA_BASE_PIPELINE_H_
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