mirror of
https://github.com/badaix/snapcast.git
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328 lines
11 KiB
C++
328 lines
11 KiB
C++
/***
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This file is part of snapcast
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Copyright (C) 2014-2021 Johannes Pohl
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <cerrno>
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#include <fcntl.h>
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#include <memory>
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#include <sys/stat.h>
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#include <unistd.h>
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#include "common/aixlog.hpp"
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#include "common/snap_exception.hpp"
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#include "common/str_compat.hpp"
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#include "alsa_stream.hpp"
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using namespace std;
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using namespace std::chrono_literals;
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namespace streamreader
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{
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static constexpr auto LOG_TAG = "AlsaStream";
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static constexpr auto kResyncTolerance = 50ms;
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// https://superuser.com/questions/597227/linux-arecord-capture-sound-card-output-rather-than-microphone-input
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// https://wiki.ubuntuusers.de/.asoundrc/
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// https://alsa.opensrc.org/Dsnoop#The_dsnoop_howto
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// https://linuxconfig.org/how-to-test-microphone-with-audio-linux-sound-architecture-alsa
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// https://www.alsa-project.org/alsa-doc/alsa-lib/_2test_2latency_8c-example.html#a30
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namespace
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{
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template <typename Rep, typename Period>
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void wait(boost::asio::steady_timer& timer, const std::chrono::duration<Rep, Period>& duration, std::function<void()> handler)
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{
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timer.expires_after(duration);
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timer.async_wait([handler = std::move(handler)](const boost::system::error_code& ec) {
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if (ec)
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{
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LOG(ERROR, LOG_TAG) << "Error during async wait: " << ec.message() << "\n";
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}
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else
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{
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handler();
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}
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});
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}
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} // namespace
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AlsaStream::AlsaStream(PcmListener* pcmListener, boost::asio::io_context& ioc, const StreamUri& uri)
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: PcmStream(pcmListener, ioc, uri), handle_(nullptr), read_timer_(ioc), silence_(0ms)
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{
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device_ = uri_.getQuery("device", "hw:0");
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send_silence_ = (uri_.getQuery("send_silence", "false") == "true");
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idle_threshold_ = std::chrono::milliseconds(std::max(cpt::stoi(uri_.getQuery("idle_threshold", "100")), 10));
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double silence_threshold_percent = 0.;
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try
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{
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silence_threshold_percent = cpt::stod(uri_.getQuery("silence_threshold_percent", "0"));
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}
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catch (...)
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{
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}
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int32_t max_amplitude = std::pow(2, sampleFormat_.bits() - 1) - 1;
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silence_threshold_ = max_amplitude * (silence_threshold_percent / 100.);
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LOG(DEBUG, LOG_TAG) << "Device: " << device_ << ", silence threshold percent: " << silence_threshold_percent
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<< ", silence threshold amplitude: " << silence_threshold_ << "\n";
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}
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void AlsaStream::start()
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{
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LOG(DEBUG, LOG_TAG) << "Start, sampleformat: " << sampleFormat_.toString() << "\n";
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// idle_bytes_ = 0;
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// max_idle_bytes_ = sampleFormat_.rate() * sampleFormat_.frameSize() * dryout_ms_ / 1000;
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initAlsa();
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chunk_ = std::make_unique<msg::PcmChunk>(sampleFormat_, chunk_ms_);
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silent_chunk_ = std::vector<char>(chunk_->payloadSize, 0);
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LOG(DEBUG, LOG_TAG) << "Chunk duration: " << chunk_->durationMs() << " ms, frames: " << chunk_->getFrameCount() << ", size: " << chunk_->payloadSize
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<< "\n";
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first_ = true;
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tvEncodedChunk_ = std::chrono::steady_clock::now();
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PcmStream::start();
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// wait(read_timer_, std::chrono::milliseconds(chunk_ms_), [this] { do_read(); });
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do_read();
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}
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void AlsaStream::stop()
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{
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PcmStream::stop();
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uninitAlsa();
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}
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void AlsaStream::initAlsa()
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{
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int err;
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unsigned int rate = sampleFormat_.rate();
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snd_pcm_format_t snd_pcm_format;
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if (sampleFormat_.bits() == 8)
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snd_pcm_format = SND_PCM_FORMAT_S8;
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else if (sampleFormat_.bits() == 16)
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snd_pcm_format = SND_PCM_FORMAT_S16_LE;
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else if ((sampleFormat_.bits() == 24) && (sampleFormat_.sampleSize() == 4))
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snd_pcm_format = SND_PCM_FORMAT_S24_LE;
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else if (sampleFormat_.bits() == 32)
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snd_pcm_format = SND_PCM_FORMAT_S32_LE;
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else
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throw SnapException("Unsupported sample format: " + cpt::to_string(sampleFormat_.bits()));
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if ((err = snd_pcm_open(&handle_, device_.c_str(), SND_PCM_STREAM_CAPTURE, SND_PCM_NONBLOCK)) < 0) // SND_PCM_NONBLOCK
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throw SnapException("Can't open device '" + device_ + "', error: " + snd_strerror(err));
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snd_pcm_hw_params_t* hw_params;
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if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0)
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throw SnapException("Can't allocate hardware parameter structure: " + string(snd_strerror(err)));
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if ((err = snd_pcm_hw_params_any(handle_, hw_params)) < 0)
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throw SnapException("Can't fill params: " + string(snd_strerror(err)));
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if ((err = snd_pcm_hw_params_set_access(handle_, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
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throw SnapException("Can't set interleaved mode: " + string(snd_strerror(err)));
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if ((err = snd_pcm_hw_params_set_format(handle_, hw_params, snd_pcm_format)) < 0)
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throw SnapException("Can't set sample format: " + string(snd_strerror(err)));
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if ((err = snd_pcm_hw_params_set_rate_near(handle_, hw_params, &rate, nullptr)) < 0)
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throw SnapException("Can't set rate: " + string(snd_strerror(err)));
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if (rate != sampleFormat_.rate())
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{
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LOG(WARNING, LOG_TAG) << "Rate is not accurate (requested: " << sampleFormat_.rate() << ", got: " << rate << "), using: " << rate << "\n";
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sampleFormat_.setFormat(rate, sampleFormat_.bits(), sampleFormat_.channels());
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}
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if ((err = snd_pcm_hw_params_set_channels(handle_, hw_params, sampleFormat_.channels())) < 0)
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throw SnapException("Can't set channel count: " + string(snd_strerror(err)));
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if ((err = snd_pcm_hw_params(handle_, hw_params)) < 0)
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throw SnapException("Can't set hardware parameters: " + string(snd_strerror(err)));
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snd_pcm_hw_params_free(hw_params);
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if ((err = snd_pcm_prepare(handle_)) < 0)
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throw SnapException("Can't prepare audio interface for use: " + string(snd_strerror(err)));
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}
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void AlsaStream::uninitAlsa()
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{
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if (handle_ != nullptr)
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{
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snd_pcm_close(handle_);
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handle_ = nullptr;
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}
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}
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bool AlsaStream::isSilent(const msg::PcmChunk& chunk) const
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{
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if (silence_threshold_ == 0)
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return (std::memcmp(chunk.payload, silent_chunk_.data(), silent_chunk_.size()) == 0);
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if (sampleFormat_.sampleSize() == 1)
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{
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auto payload = chunk.getPayload<int8_t>();
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for (size_t n = 0; n < payload.second; ++n)
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{
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if (abs(payload.first[n]) > silence_threshold_)
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return false;
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}
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}
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else if (sampleFormat_.sampleSize() == 2)
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{
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auto payload = chunk.getPayload<int16_t>();
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for (size_t n = 0; n < payload.second; ++n)
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{
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if (abs(payload.first[n]) > silence_threshold_)
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return false;
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}
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}
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else if (sampleFormat_.sampleSize() == 4)
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{
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auto payload = chunk.getPayload<int32_t>();
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for (size_t n = 0; n < payload.second; ++n)
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{
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if (abs(payload.first[n]) > silence_threshold_)
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return false;
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}
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}
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return true;
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}
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void AlsaStream::do_read()
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{
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try
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{
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if (first_)
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{
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LOG(TRACE, LOG_TAG) << "First read, initializing nextTick to now\n";
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nextTick_ = std::chrono::steady_clock::now();
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}
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int toRead = chunk_->payloadSize;
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auto duration = chunk_->duration<std::chrono::nanoseconds>();
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int len = 0;
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do
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{
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int count = snd_pcm_readi(handle_, chunk_->payload + len, (toRead - len) / chunk_->format.frameSize());
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if (count == -EAGAIN)
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{
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LOG(INFO, LOG_TAG) << "No data availabale, playing silence.\n";
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// no data available, fill with silence
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memset(chunk_->payload + len, 0, toRead - len);
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// idle_bytes_ += toRead - len;
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break;
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}
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else if (count == 0)
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{
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throw SnapException("end of file");
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}
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else if (count < 0)
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{
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// ESTRPIPE
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LOG(ERROR, LOG_TAG) << "Error reading PCM data: " << snd_strerror(count) << " (code: " << count << ")\n";
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first_ = true;
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uninitAlsa();
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initAlsa();
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continue;
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}
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else
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{
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// LOG(TRACE, LOG_TAG) << "count: " << count << ", len: " << len << ", toRead: " << toRead << "\n";
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len += count * chunk_->format.frameSize();
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}
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} while (len < toRead);
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if (isSilent(*chunk_))
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{
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silence_ += chunk_->duration<std::chrono::microseconds>();
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if (silence_ > idle_threshold_)
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{
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setState(ReaderState::kIdle);
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}
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}
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else
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{
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silence_ = 0ms;
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if ((state_ == ReaderState::kIdle) && !send_silence_)
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first_ = true;
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setState(ReaderState::kPlaying);
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}
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// LOG(DEBUG, LOG_TAG) << "Received " << len << "/" << toRead << " bytes\n";
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if (first_)
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{
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first_ = false;
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// initialize the stream's base timestamp to now minus the chunk's duration
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tvEncodedChunk_ = std::chrono::steady_clock::now() - duration;
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}
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if ((state_ == ReaderState::kPlaying) || ((state_ == ReaderState::kIdle) && send_silence_))
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{
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chunkRead(*chunk_);
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}
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nextTick_ += duration;
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auto currentTick = std::chrono::steady_clock::now();
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auto next_read = nextTick_ - currentTick;
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if (next_read >= 0ms)
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{
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// LOG(DEBUG, LOG_TAG) << "Next read: " << std::chrono::duration_cast<std::chrono::milliseconds>(next_read).count() << "\n";
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// synchronize reads to an interval of chunk_ms_
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wait(read_timer_, nextTick_ - currentTick, [this] { do_read(); });
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return;
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}
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else if (next_read >= -kResyncTolerance)
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{
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LOG(INFO, LOG_TAG) << "next read < 0 (" << getName() << "): " << std::chrono::duration_cast<std::chrono::microseconds>(next_read).count() / 1000.
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<< " ms\n ";
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do_read();
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}
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else
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{
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// reading chunk_ms_ took longer than chunk_ms_
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resync(-next_read);
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first_ = true;
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wait(read_timer_, nextTick_ - currentTick, [this] { do_read(); });
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}
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lastException_ = "";
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}
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catch (const std::exception& e)
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{
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if (lastException_ != e.what())
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{
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LOG(ERROR, LOG_TAG) << "Exception: " << e.what() << std::endl;
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lastException_ = e.what();
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}
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first_ = true;
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uninitAlsa();
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initAlsa();
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wait(read_timer_, 100ms, [this] { do_read(); });
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}
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}
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} // namespace streamreader
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