shaka-packager/packager/media/base/media_handler.h

196 lines
7.5 KiB
C++

// Copyright 2017 Google Inc. 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_BASE_MEDIA_HANDLER_H_
#define PACKAGER_MEDIA_BASE_MEDIA_HANDLER_H_
#include <map>
#include <memory>
#include <utility>
#include "packager/media/base/media_sample.h"
#include "packager/media/base/status.h"
#include "packager/media/base/stream_info.h"
namespace shaka {
namespace media {
enum class StreamDataType {
kUnknown,
kPeriodInfo,
kStreamInfo,
kMediaSample,
kMediaEvent,
kSegmentInfo,
};
// TODO(kqyang): Define these structures.
struct PeriodInfo {};
struct MediaEvent {};
struct SegmentInfo {
bool is_subsegment = false;
bool is_encrypted = false;
int64_t start_timestamp = -1;
int64_t duration = 0;
// This is only available if key rotation is enabled. Note that we may have
// a |key_rotation_encryption_config| even if the segment is not encrypted,
// which is the case for clear lead.
std::shared_ptr<EncryptionConfig> key_rotation_encryption_config;
};
// TODO(kqyang): Should we use protobuf?
struct StreamData {
size_t stream_index = static_cast<size_t>(-1);
StreamDataType stream_data_type = StreamDataType::kUnknown;
std::shared_ptr<PeriodInfo> period_info;
std::shared_ptr<StreamInfo> stream_info;
std::shared_ptr<MediaSample> media_sample;
std::shared_ptr<MediaEvent> media_event;
std::shared_ptr<SegmentInfo> segment_info;
};
/// MediaHandler is the base media processing unit. Media handlers transform
/// the input streams and propagate the outputs to downstream media handlers.
/// There are three different types of media handlers:
/// 1) Single input single output
/// This is the most basic handler. It only supports one input and one
/// output with both index as 0.
/// 2) Multiple inputs multiple outputs
/// The number of outputs must be equal to the number of inputs. The
/// output stream at a specific index comes from the input stream at the
/// same index. Different streams usually share a common resource, although
/// they may be independent. One example of this is encryptor handler.
/// 3) Single input multiple outputs
/// The input stream is splitted into multiple output streams. One example
/// of this is trick play handler.
/// Other types of media handlers are disallowed and not supported.
class MediaHandler {
public:
MediaHandler() = default;
virtual ~MediaHandler() = default;
/// Connect downstream handler at the specified output stream index.
Status SetHandler(size_t output_stream_index,
std::shared_ptr<MediaHandler> handler);
/// Connect downstream handler to the next availble output stream index.
Status AddHandler(std::shared_ptr<MediaHandler> handler) {
return SetHandler(next_output_stream_index_, handler);
}
/// Initialize the handler and downstream handlers. Note that it should be
/// called after setting up the graph before running the graph.
Status Initialize();
/// Validate if the handler is connected to its upstream handler.
bool IsConnected() { return num_input_streams_ > 0; }
protected:
/// Internal implementation of initialize. Note that it should only initialize
/// the MediaHandler itself. Downstream handlers are handled in Initialize().
virtual Status InitializeInternal() = 0;
/// Process the incoming stream data. Note that (1) stream_data.stream_index
/// should be the input stream index; (2) The implementation needs to call
/// DispatchXxx to dispatch the processed stream data to the downstream
/// handlers after finishing processing if needed.
virtual Status Process(std::unique_ptr<StreamData> stream_data) = 0;
/// Event handler for flush request at the specific input stream index.
virtual Status OnFlushRequest(size_t input_stream_index);
/// Validate if the stream at the specified index actually exists.
virtual bool ValidateOutputStreamIndex(size_t stream_index) const;
/// Dispatch the stream data to downstream handlers. Note that
/// stream_data.stream_index should be the output stream index.
Status Dispatch(std::unique_ptr<StreamData> stream_data);
/// Dispatch the period info to downstream handlers.
Status DispatchPeriodInfo(size_t stream_index,
std::shared_ptr<PeriodInfo> period_info) {
std::unique_ptr<StreamData> stream_data(new StreamData);
stream_data->stream_index = stream_index;
stream_data->stream_data_type = StreamDataType::kPeriodInfo;
stream_data->period_info = std::move(period_info);
return Dispatch(std::move(stream_data));
}
/// Dispatch the stream info to downstream handlers.
Status DispatchStreamInfo(size_t stream_index,
std::shared_ptr<StreamInfo> stream_info) {
std::unique_ptr<StreamData> stream_data(new StreamData);
stream_data->stream_index = stream_index;
stream_data->stream_data_type = StreamDataType::kStreamInfo;
stream_data->stream_info = std::move(stream_info);
return Dispatch(std::move(stream_data));
}
/// Dispatch the media sample to downstream handlers.
Status DispatchMediaSample(size_t stream_index,
std::shared_ptr<MediaSample> media_sample) {
std::unique_ptr<StreamData> stream_data(new StreamData);
stream_data->stream_index = stream_index;
stream_data->stream_data_type = StreamDataType::kMediaSample;
stream_data->media_sample = std::move(media_sample);
return Dispatch(std::move(stream_data));
}
/// Dispatch the media event to downstream handlers.
Status DispatchMediaEvent(size_t stream_index,
std::shared_ptr<MediaEvent> media_event) {
std::unique_ptr<StreamData> stream_data(new StreamData);
stream_data->stream_index = stream_index;
stream_data->stream_data_type = StreamDataType::kMediaEvent;
stream_data->media_event = std::move(media_event);
return Dispatch(std::move(stream_data));
}
/// Dispatch the segment info to downstream handlers.
Status DispatchSegmentInfo(size_t stream_index,
std::shared_ptr<SegmentInfo> segment_info) {
std::unique_ptr<StreamData> stream_data(new StreamData);
stream_data->stream_index = stream_index;
stream_data->stream_data_type = StreamDataType::kSegmentInfo;
stream_data->segment_info = std::move(segment_info);
return Dispatch(std::move(stream_data));
}
/// Flush the downstream connected at the specified output stream index.
Status FlushDownstream(size_t output_stream_index);
/// Flush all connected downstreams.
Status FlushAllDownstreams();
bool initialized() { return initialized_; }
size_t num_input_streams() const { return num_input_streams_; }
size_t next_output_stream_index() const { return next_output_stream_index_; }
const std::map<size_t, std::pair<std::shared_ptr<MediaHandler>, size_t>>&
output_handlers() {
return output_handlers_;
}
private:
MediaHandler(const MediaHandler&) = delete;
MediaHandler& operator=(const MediaHandler&) = delete;
bool initialized_ = false;
// Number of input streams.
size_t num_input_streams_ = 0;
// The next available output stream index, used by AddHandler.
size_t next_output_stream_index_ = 0;
// output stream index -> {output handler, output handler input stream index}
// map.
std::map<size_t, std::pair<std::shared_ptr<MediaHandler>, size_t>>
output_handlers_;
};
} // namespace media
} // namespace shaka
#endif // PACKAGER_MEDIA_BASE_MEDIA_HANDLER_H_