shaka-packager/packager/media/chunking/cue_alignment_handler.h

94 lines
3.4 KiB
C++

// Copyright 2018 Google LLC. All rights reserved.
//
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file or at
// https://developers.google.com/open-source/licenses/bsd
#ifndef PACKAGER_MEDIA_CHUNKING_CUE_ALIGNMENT_HANDLER_
#define PACKAGER_MEDIA_CHUNKING_CUE_ALIGNMENT_HANDLER_
#include <deque>
#include <list>
#include "packager/media/base/media_handler.h"
#include "packager/media/chunking/sync_point_queue.h"
namespace shaka {
namespace media {
/// The cue alignment handler is a N-to-N handler that will inject CueEvents
/// into all streams. It will align the cues across streams (and handlers)
/// using a shared SyncPointQueue.
///
/// There should be a cue alignment handler per demuxer/thread and not per
/// stream. A cue alignment handler must be one per thread in order to properly
/// manage blocking.
class CueAlignmentHandler : public MediaHandler {
public:
explicit CueAlignmentHandler(SyncPointQueue* sync_points);
~CueAlignmentHandler() = default;
private:
CueAlignmentHandler(const CueAlignmentHandler&) = delete;
CueAlignmentHandler& operator=(const CueAlignmentHandler&) = delete;
struct StreamState {
// Information for the stream.
std::shared_ptr<const StreamInfo> info;
// Cached samples that cannot be dispatched. All the samples should be at or
// after |hint|.
std::list<std::unique_ptr<StreamData>> samples;
// If set, the stream is pending to be flushed.
bool to_be_flushed = false;
// Only set for text stream.
double max_text_sample_end_time_seconds = 0;
// A list of cues that the stream should inject between media samples. When
// there are no cues, the stream should run up to the hint.
std::list<std::unique_ptr<StreamData>> cues;
};
// MediaHandler overrides.
Status InitializeInternal() override;
Status Process(std::unique_ptr<StreamData> data) override;
Status OnFlushRequest(size_t stream_index) override;
// Internal handling functions for different stream data.
Status OnStreamInfo(std::unique_ptr<StreamData> data);
Status OnVideoSample(std::unique_ptr<StreamData> sample);
Status OnNonVideoSample(std::unique_ptr<StreamData> sample);
Status OnSample(std::unique_ptr<StreamData> sample);
// Update stream states with new sync point.
Status UseNewSyncPoint(std::shared_ptr<const CueEvent> new_sync);
// Check if everyone is waiting for new hint points.
bool EveryoneWaitingAtHint() const;
// Dispatch or save incoming sample.
Status AcceptSample(std::unique_ptr<StreamData> sample,
StreamState* stream_state);
// Dispatch all samples and cues (in the correct order) for the given stream.
Status RunThroughSamples(StreamState* stream);
SyncPointQueue* const sync_points_ = nullptr;
std::deque<StreamState> stream_states_;
// A common hint used by all streams. When a new cue is given to all streams,
// the hint will be updated. The hint will always be larger than any cue. The
// hint represents the min time in seconds for the next cue appear. The hints
// are based off the un-promoted cue event times in |sync_points_|.
//
// When a video stream passes the hint, it will promote the corresponding cue
// event. If all streams get to the hint and there are no video streams, the
// thread will block until |sync_points_| gives back a promoted cue event.
double hint_;
};
} // namespace media
} // namespace shaka
#endif // PACKAGER_MEDIA_CHUNKING_CUE_ALIGNMENT_HANDLER_