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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_VIDEO_RENDERER_H_
#define MEDIA_BASE_VIDEO_RENDERER_H_
#include "base/callback_forward.h"
#include "media/base/media_export.h"
#include "media/base/pipeline_status.h"
#include "media/base/time_source.h"
#include "third_party/abseil-cpp/absl/types/optional.h"
namespace media {
class CdmContext;
class DemuxerStream;
class RendererClient;
class MEDIA_EXPORT VideoRenderer {
public:
VideoRenderer();
VideoRenderer(const VideoRenderer&) = delete;
VideoRenderer& operator=(const VideoRenderer&) = delete;
// Stops all operations and fires all pending callbacks.
virtual ~VideoRenderer();
// Initializes a VideoRenderer with |stream|, executing |init_cb| upon
// completion. If initialization fails, only |init_cb|
// (not RendererClient::OnError) will be called.
//
// |cdm_context| can be used to handle encrypted streams. May be null if the
// stream is not encrypted.
//
// |wall_clock_time_cb| is used to convert media timestamps into wallclock
// timestamps.
//
// VideoRenderer may be reinitialized for playback of a different demuxer
// stream by calling Initialize again when the renderer is in a flushed
// state (i.e. after Flush call, but before StartPlayingFrom). This is used
// for media track switching.
virtual void Initialize(DemuxerStream* stream,
CdmContext* cdm_context,
RendererClient* client,
const TimeSource::WallClockTimeCB& wall_clock_time_cb,
PipelineStatusCallback init_cb) = 0;
// Discards any video data and stops reading from |stream|, executing
// |callback| when completed.
//
// Clients should expect |buffering_state_cb| to be called with
// BUFFERING_HAVE_NOTHING while flushing is in progress.
virtual void Flush(base::OnceClosure callback) = 0;
// Starts playback at |timestamp| by reading from |stream| and decoding and
// rendering video.
//
// Only valid to call after a successful Initialize() or Flush().
virtual void StartPlayingFrom(base::TimeDelta timestamp) = 0;
// Called when time starts or stops moving. Time progresses when a base time
// has been set and the playback rate is > 0. If either condition changes,
// time stops progressing.
virtual void OnTimeProgressing() = 0;
virtual void OnTimeStopped() = 0;
// Sets a hint indicating target latency. See comment in header for
// media::Renderer::SetLatencyHint().
// |latency_hint| may be nullopt to indicate the hint has been cleared
// (restore UA default).
virtual void SetLatencyHint(absl::optional<base::TimeDelta> latency_hint) = 0;
};
} // namespace media
#endif // MEDIA_BASE_VIDEO_RENDERER_H_