snapcast/server/streamreader/pcm_stream.hpp
2025-03-02 20:28:17 +01:00

261 lines
8.7 KiB
C++

/***
This file is part of snapcast
Copyright (C) 2014-2025 Johannes Pohl
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
***/
#pragma once
// local headers
#include "common/error_code.hpp"
#include "common/json.hpp"
#include "common/message/codec_header.hpp"
#include "common/sample_format.hpp"
#include "common/stream_uri.hpp"
#include "encoder/encoder.hpp"
#include "jsonrpcpp.hpp"
#include "properties.hpp"
#include "server_settings.hpp"
#include "stream_control.hpp"
// 3rd party headers
#include <boost/asio/io_context.hpp>
#include <boost/asio/read_until.hpp>
#include <boost/asio/steady_timer.hpp>
// standard headers
#include <atomic>
#include <mutex>
#include <string>
#include <vector>
using json = nlohmann::json;
namespace streamreader
{
class PcmStream;
enum class ReaderState
{
kUnknown = 0,
kIdle = 1,
kPlaying = 2,
kDisabled = 3
};
static std::string to_string(const ReaderState& reader_state)
{
switch (reader_state)
{
case ReaderState::kIdle:
return "idle";
case ReaderState::kPlaying:
return "playing";
case ReaderState::kDisabled:
return "disabled";
case ReaderState::kUnknown:
default:
return "unknown";
}
}
static std::ostream& operator<<(std::ostream& os, const ReaderState& reader_state)
{
os << to_string(reader_state);
return os;
}
static constexpr auto kUriCodec = "codec";
static constexpr auto kUriName = "name";
static constexpr auto kUriSampleFormat = "sampleformat";
static constexpr auto kUriChunkMs = "chunk_ms";
static constexpr auto kControlScript = "controlscript";
static constexpr auto kControlScriptParams = "controlscriptparams";
/// Reads and decodes PCM data
/**
* Reads PCM and passes the data to an encoder.
* Implements EncoderListener to get the encoded data.
* Data is passed to the PcmStream::Listener
*/
class PcmStream : public std::enable_shared_from_this<PcmStream>
{
public:
/// Callback interface for users of PcmStream
/// Users of PcmStream should implement this to get the data
class Listener
{
public:
/// Properties of @p pcmStream changed to @p properties
virtual void onPropertiesChanged(const PcmStream* pcmStream, const Properties& properties) = 0;
/// State of @p pcmStream changed to @p state
virtual void onStateChanged(const PcmStream* pcmStream, ReaderState state) = 0;
/// Chunk @p chunk of @p pcmStream has read
virtual void onChunkRead(const PcmStream* pcmStream, const msg::PcmChunk& chunk) = 0;
/// Chunk @p chunk with duration @p duration of stream @pcmStream has been encoded
virtual void onChunkEncoded(const PcmStream* pcmStream, std::shared_ptr<msg::PcmChunk> chunk, double duration) = 0;
/// Stream @p pcmStream muissed to read audio with duration @p ms
virtual void onResync(const PcmStream* pcmStream, double ms) = 0;
};
using ResultHandler = std::function<void(const snapcast::ErrorCode& ec)>;
/// c'tor. Encoded PCM data is passed to the PcmStream::Listener
PcmStream(PcmStream::Listener* pcmListener, boost::asio::io_context& ioc, const ServerSettings& server_settings, const StreamUri& uri);
/// d'tor
virtual ~PcmStream();
/// Start the stream reader, init the encoder and optionally the stream control
virtual void start();
/// Stop the stream reader
virtual void stop();
/// @return the codec header of the stream
virtual std::shared_ptr<msg::CodecHeader> getHeader();
/// @return the uri of the stream, as configured in snapserver.conf
virtual const StreamUri& getUri() const;
/// @return the name of the stream
virtual const std::string& getName() const;
/// @return the id of the stream
virtual const std::string& getId() const;
/// @return the sample format of the stream
virtual const SampleFormat& getSampleFormat() const;
/// @return the codec of the stream
virtual std::string getCodec() const;
/// @return stream properties
const Properties& getProperties() const;
// Setter for properties
/// Set shuffle property
virtual void setShuffle(bool shuffle, ResultHandler&& handler);
/// Set loop property
virtual void setLoopStatus(LoopStatus status, ResultHandler&& handler);
/// Set volume property
virtual void setVolume(uint16_t volume, ResultHandler&& handler);
/// Set mute property
virtual void setMute(bool mute, ResultHandler&& handler);
/// Set playback rate property
virtual void setRate(float rate, ResultHandler&& handler);
// Control commands
/// Set position
virtual void setPosition(std::chrono::milliseconds position, ResultHandler&& handler);
/// Seek
virtual void seek(std::chrono::milliseconds offset, ResultHandler&& handler);
/// Play next
virtual void next(ResultHandler&& handler);
/// Play previous
virtual void previous(ResultHandler&& handler);
/// Pause
virtual void pause(ResultHandler&& handler);
/// Toggle play/pause
virtual void playPause(ResultHandler&& handler);
/// Stop
virtual void stop(ResultHandler&& handler);
/// Play
virtual void play(ResultHandler&& handler);
/// Get stream reader state (idle/playing)
virtual ReaderState getState() const;
/// Stream description to json
virtual json toJson() const;
/// Add a pcm listener
void addListener(PcmStream::Listener* pcmListener);
protected:
/// Stream is active (started?
std::atomic<bool> active_;
/// check if the volume of the \p chunk is below the silence threshold
bool isSilent(const msg::PcmChunk& chunk) const;
/// Set reader state
void setState(ReaderState newState);
/// A @p chunk has been read
void chunkRead(const msg::PcmChunk& chunk);
/// Announce resync
void resync(const std::chrono::nanoseconds& duration);
/// Called by @p encoder when a @p chunk of @p duration ms has been encoded
void chunkEncoded(const encoder::Encoder& encoder, const std::shared_ptr<msg::PcmChunk>& chunk, double duration);
/// Set stream properties
void setProperties(const Properties& properties);
/// Poll stream properties
void pollProperties();
// script callbacks
/// Request received from control script
void onControlRequest(const jsonrpcpp::Request& request);
/// Notification received from control script
void onControlNotification(const jsonrpcpp::Notification& notification);
/// Log message received from control script via stderr
void onControlLog(std::string line);
/// Send request to stream control script
void sendRequest(const std::string& method, const jsonrpcpp::Parameter& params, ResultHandler&& handler);
/// Executor for synchronous IO
boost::asio::strand<boost::asio::any_io_executor> strand_;
/// Current abolute time of the last encoded chunk
std::chrono::time_point<std::chrono::steady_clock> tvEncodedChunk_;
/// Listeners for PCM events
std::vector<PcmStream::Listener*> pcmListeners_;
/// URI of this stream
StreamUri uri_;
/// Sampleformat of this stream
SampleFormat sampleFormat_;
/// Chunk read duration
size_t chunk_ms_;
/// Encoder (PCM, flac, vorbus, opus)
std::unique_ptr<encoder::Encoder> encoder_;
/// Name of this stream
std::string name_;
/// Stream state
std::atomic<ReaderState> state_;
/// Stream properies
Properties properties_;
/// Server settings
ServerSettings server_settings_;
/// Stream controller (play, pause, next, ...)
std::unique_ptr<StreamControl> stream_ctrl_;
/// Id of the last request sent to the stream controller
std::atomic<int> req_id_;
/// Property poll timer
boost::asio::steady_timer property_timer_;
/// Protect properties
mutable std::recursive_mutex mutex_;
/// If a chunk's max amplitude is below the threshold, it is considered silent
int32_t silence_threshold_ = 0;
/// Current chunk
std::unique_ptr<msg::PcmChunk> chunk_;
/// Silent chunk (all 0), for fast silence detection (memcmp)
std::vector<char> silent_chunk_;
};
} // namespace streamreader