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snapcast/client/stream.cpp

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/***
This file is part of snapcast
Copyright (C) 2014-2020 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/>.
***/
#ifndef NOMINMAX
#define NOMINMAX
#endif // NOMINMAX
#include "stream.hpp"
#include "common/aixlog.hpp"
#include "time_provider.hpp"
#include <cmath>
#include <iostream>
#include <string.h>
using namespace std;
namespace cs = chronos;
static constexpr auto LOG_TAG = "Stream";
static constexpr auto kCorrectionBegin = 100us;
Stream::Stream(const SampleFormat& in_format, const SampleFormat& out_format)
: in_format_(in_format), median_(0), shortMedian_(0), lastUpdate_(0), playedFrames_(0), correctAfterXFrames_(0), bufferMs_(cs::msec(500)), frame_delta_(0),
hard_sync_(true)
{
buffer_.setSize(500);
shortBuffer_.setSize(100);
miniBuffer_.setSize(20);
format_ = in_format_;
if (out_format.isInitialized())
{
format_.setFormat(out_format.rate() != 0 ? out_format.rate() : format_.rate(), out_format.bits() != 0 ? out_format.bits() : format_.bits(),
out_format.channels() != 0 ? out_format.channels() : format_.channels());
}
/*
48000 x
------- = -----
47999,2 x - 1
x = 1,000016667 / (1,000016667 - 1)
*/
// setRealSampleRate(format_.rate());
#ifdef HAS_SOXR
soxr_ = nullptr;
if ((format_.rate() != in_format_.rate()) || (format_.bits() != in_format_.bits()))
{
LOG(INFO, LOG_TAG) << "Resampling from " << in_format_.toString() << " to " << format_.toString() << "\n";
soxr_error_t error;
soxr_datatype_t in_type = SOXR_INT16_I;
soxr_datatype_t out_type = SOXR_INT16_I;
if (in_format_.sampleSize() > 2)
in_type = SOXR_INT32_I;
if (format_.sampleSize() > 2)
out_type = SOXR_INT32_I;
soxr_io_spec_t iospec = soxr_io_spec(in_type, out_type);
// HQ should be fine: http://sox.sourceforge.net/Docs/FAQ
soxr_quality_spec_t q_spec = soxr_quality_spec(SOXR_HQ, 0);
soxr_ = soxr_create(static_cast<double>(in_format_.rate()), static_cast<double>(format_.rate()), format_.channels(), &error, &iospec, &q_spec, NULL);
if (error)
{
LOG(ERROR, LOG_TAG) << "Error soxr_create: " << error << "\n";
soxr_ = nullptr;
}
// initialize the buffer with 20ms (~latency of the reampler)
resample_buffer_.resize(format_.frameSize() * static_cast<uint16_t>(ceil(format_.msRate() * 20)));
}
#endif
}
Stream::~Stream()
{
#ifdef HAS_SOXR
if (soxr_)
soxr_delete(soxr_);
#endif
}
void Stream::setRealSampleRate(double sampleRate)
{
if (sampleRate == format_.rate())
{
correctAfterXFrames_ = 0;
}
else
{
correctAfterXFrames_ = static_cast<int32_t>(round((format_.rate() / sampleRate) / (format_.rate() / sampleRate - 1.)));
// LOG(TRACE, LOG_TAG) << "Correct after X: " << correctAfterXFrames_ << " (Real rate: " << sampleRate << ", rate: " << format_.rate() << ")\n";
}
}
void Stream::setBufferLen(size_t bufferLenMs)
{
bufferMs_ = cs::msec(bufferLenMs);
}
void Stream::clearChunks()
{
while (chunks_.size() > 0)
chunks_.pop();
resetBuffers();
}
void Stream::addChunk(unique_ptr<msg::PcmChunk> chunk)
{
// drop chunk if it's too old. Just in case, this shouldn't happen.
cs::usec age = std::chrono::duration_cast<cs::usec>(TimeProvider::serverNow() - chunk->start());
if (age > 5s + bufferMs_)
return;
// LOG(DEBUG, LOG_TAG) << "new chunk: " << chunk->durationMs() << " ms, Chunks: " << chunks_.size() << "\n";
#ifndef HAS_SOXR
chunks_.push(move(chunk));
#else
if (soxr_ == nullptr)
{
chunks_.push(move(chunk));
}
else
{
if (in_format_.bits() == 24)
{
// sox expects 32 bit input, shift 8 bits left
int32_t* frames = (int32_t*)chunk->payload;
for (size_t n = 0; n < chunk->getSampleCount(); ++n)
frames[n] = frames[n] << 8;
}
size_t idone;
size_t odone;
auto resample_buffer_framesize = resample_buffer_.size() / format_.frameSize();
auto error = soxr_process(soxr_, chunk->payload, chunk->getFrameCount(), &idone, resample_buffer_.data(), resample_buffer_framesize, &odone);
if (error)
{
LOG(ERROR, LOG_TAG) << "Error soxr_process: " << error << "\n";
}
else
{
LOG(TRACE, LOG_TAG) << "Resample idone: " << idone << "/" << chunk->getFrameCount() << ", odone: " << odone << "/"
<< resample_buffer_.size() / format_.frameSize() << ", delay: " << soxr_delay(soxr_) << "\n";
// some data has been resampled (odone frames) and some is still in the pipe (soxr_delay frames)
if (odone > 0)
{
// get the resamples ts from the input ts
auto input_end_ts = chunk->start() + chunk->duration<std::chrono::microseconds>();
double resampled_ms = (odone + soxr_delay(soxr_)) / format_.msRate();
auto resampled_start = input_end_ts - std::chrono::microseconds(static_cast<int>(resampled_ms * 1000.));
auto resampled_chunk = new msg::PcmChunk(format_, 0);
auto us = chrono::duration_cast<chrono::microseconds>(resampled_start.time_since_epoch()).count();
resampled_chunk->timestamp.sec = static_cast<int32_t>(us / 1000000);
resampled_chunk->timestamp.usec = static_cast<int32_t>(us % 1000000);
// copy from the resample_buffer to the resampled chunk
resampled_chunk->payloadSize = static_cast<uint32_t>(odone * format_.frameSize());
resampled_chunk->payload = (char*)realloc(resampled_chunk->payload, resampled_chunk->payloadSize);
memcpy(resampled_chunk->payload, resample_buffer_.data(), resampled_chunk->payloadSize);
if (format_.bits() == 24)
{
// sox has quantized to 32 bit, shift 8 bits right
int32_t* frames = (int32_t*)resampled_chunk->payload;
for (size_t n = 0; n < resampled_chunk->getSampleCount(); ++n)
{
// +128 to round to the nearest so that quantisation steps are distributed evenly
frames[n] = (frames[n] + 128) >> 8;
if (frames[n] > 0x7fffffff)
frames[n] = 0x7fffffff;
}
}
chunks_.push(shared_ptr<msg::PcmChunk>(resampled_chunk));
// check if the resample_buffer is large enough, or if soxr was using all available space
if (odone == resample_buffer_framesize)
{
// buffer for resampled data too small, add space for 5ms
resample_buffer_.resize(resample_buffer_.size() + format_.frameSize() * static_cast<uint16_t>(ceil(format_.msRate() * 5)));
LOG(DEBUG, LOG_TAG) << "Resample buffer completely filled, adding space for 5ms; new buffer size: " << resample_buffer_.size()
<< " bytes\n";
}
// //LOG(TRACE, LOG_TAG) << "ts: " << out->timestamp.sec << "s, " << out->timestamp.usec/1000.f << " ms, duration: " << odone / format_.msRate()
// << "\n";
// int64_t next_us = us + static_cast<int64_t>(odone / format_.msRate() * 1000);
// LOG(TRACE, LOG_TAG) << "ts: " << us << ", next: " << next_us << ", diff: " << next_us_ - us << "\n";
// next_us_ = next_us;
}
}
}
#endif
}
bool Stream::waitForChunk(const std::chrono::milliseconds& timeout) const
{
return chunks_.wait_for(timeout);
}
void Stream::getSilentPlayerChunk(void* outputBuffer, uint32_t frames) const
{
memset(outputBuffer, 0, frames * format_.frameSize());
}
cs::time_point_clk Stream::getNextPlayerChunk(void* outputBuffer, uint32_t frames)
{
if (!chunk_ && !chunks_.try_pop(chunk_))
throw 0;
cs::time_point_clk tp = chunk_->start();
uint32_t read = 0;
while (read < frames)
{
read += chunk_->readFrames(static_cast<char*>(outputBuffer) + read * format_.frameSize(), frames - read);
if (chunk_->isEndOfChunk() && !chunks_.try_pop(chunk_))
throw 0;
}
return tp;
}
cs::time_point_clk Stream::getNextPlayerChunk(void* outputBuffer, uint32_t frames, int32_t framesCorrection)
{
if (framesCorrection < 0 && frames + framesCorrection <= 0)
{
// Avoid underflow in new char[] constructor.
framesCorrection = -static_cast<int32_t>(frames) + 1;
}
if (framesCorrection == 0)
return getNextPlayerChunk(outputBuffer, frames);
frame_delta_ -= framesCorrection;
uint32_t toRead = frames + framesCorrection;
if (toRead * format_.frameSize() > read_buffer_.size())
read_buffer_.resize(toRead * format_.frameSize());
cs::time_point_clk tp = getNextPlayerChunk(read_buffer_.data(), toRead);
const auto max = framesCorrection < 0 ? frames : toRead;
// Divide the buffer into one more slice than frames that need to be dropped.
// We will drop/repeat 0 frames from the first slice, 1 frame from the second, ..., and framesCorrection frames from the last slice.
size_t slices = abs(framesCorrection) + 1;
if (slices > max)
{
// We cannot have more slices than frames, because that would cause
// size = 0 -> pos = 0 -> pos - n < 0 in the loop below
// Overwriting slices effectively corrects less frames than asked for in framesCorrection.
slices = max;
}
// Size of each slice. The last slice may be bigger.
auto size = max / slices;
// LOG(TRACE, LOG_TAG) << "getNextPlayerChunk, frames: " << frames << ", correction: " << framesCorrection << " (" << toRead << "), slices: " << slices
// << "\n";
size_t pos = 0;
for (size_t n = 0; n < slices; ++n)
{
// Adjust size in the last iteration, because the last slice may be bigger
if (n + 1 == slices)
size = max - pos;
if (framesCorrection < 0)
{
// Read one frame less per slice from the input, but write a duplicated frame per slice to the output
// LOG(TRACE, LOG_TAG) << "duplicate - requested: " << frames << ", read: " << toRead << ", slice: " << n << ", size: " << size << ", out pos: " <<
// pos << ", source pos: " << pos - n << "\n";
memcpy(static_cast<char*>(outputBuffer) + pos * format_.frameSize(), read_buffer_.data() + (pos - n) * format_.frameSize(),
size * format_.frameSize());
}
else
{
// Read all input frames, but skip a frame per slice when writing to the output.
// LOG(TRACE, LOG_TAG) << "remove - requested: " << frames << ", read: " << toRead << ", slice: " << n << ", size: " << size << ", out pos: " << pos
// - n << ", source pos: " << pos << "\n";
memcpy(static_cast<char*>(outputBuffer) + (pos - n) * format_.frameSize(), read_buffer_.data() + pos * format_.frameSize(),
size * format_.frameSize());
}
pos += size;
}
return tp;
}
void Stream::updateBuffers(chronos::usec::rep age)
{
buffer_.add(age);
miniBuffer_.add(age);
shortBuffer_.add(age);
}
void Stream::resetBuffers()
{
buffer_.clear();
miniBuffer_.clear();
shortBuffer_.clear();
}
bool Stream::getPlayerChunk(void* outputBuffer, const cs::usec& outputBufferDacTime, uint32_t frames)
{
if (outputBufferDacTime > bufferMs_)
{
LOG(INFO, LOG_TAG) << "outputBufferDacTime > bufferMs: " << cs::duration<cs::msec>(outputBufferDacTime) << " > " << cs::duration<cs::msec>(bufferMs_)
<< "\n";
return false;
}
time_t now = time(nullptr);
if (!chunk_ && !chunks_.try_pop(chunk_))
{
if (now != lastUpdate_)
{
lastUpdate_ = now;
LOG(INFO, LOG_TAG) << "no chunks available\n";
}
return false;
}
/// we have a chunk
/// age = chunk age (server now - rec time: some positive value) - buffer (e.g. 1000ms) + time to DAC
/// age = 0 => play now
/// age < 0 => play in -age => wait for a while, play silence in the meantime
/// age > 0 => too old => throw them away
try
{
if (hard_sync_)
{
cs::nsec req_chunk_duration = cs::nsec(static_cast<cs::nsec::rep>(frames / format_.nsRate()));
cs::usec age = std::chrono::duration_cast<cs::usec>(TimeProvider::serverNow() - chunk_->start()) - bufferMs_ + outputBufferDacTime;
// LOG(INFO, LOG_TAG) << "age: " << age.count() / 1000 << ", buffer: " <<
// std::chrono::duration_cast<chrono::milliseconds>(req_chunk_duration).count() << "\n";
if (age < -req_chunk_duration)
{
// the oldest chunk (top of the stream) is too young for the buffer
// e.g. age = -100ms (=> should be played in 100ms)
// but the requested chunk duration is 50ms, so there is not data in this iteration available
getSilentPlayerChunk(outputBuffer, frames);
return true;
}
else
{
if (age.count() > 0)
{
LOG(DEBUG, LOG_TAG) << "age > 0: " << age.count() / 1000 << "ms\n";
// age > 0: the top of the stream is too old. We must fast foward.
// delete the current chunk, it's too old. This will avoid an endless loop if there is no chunk in the queue.
chunk_ = nullptr;
while (chunks_.try_pop(chunk_))
{
age = std::chrono::duration_cast<cs::usec>(TimeProvider::serverNow() - chunk_->start()) - bufferMs_ + outputBufferDacTime;
LOG(DEBUG, LOG_TAG) << "age: " << age.count() / 1000 << ", requested chunk_duration: "
<< std::chrono::duration_cast<std::chrono::milliseconds>(req_chunk_duration).count()
<< ", duration: " << chunk_->duration<std::chrono::milliseconds>().count() << "\n";
if (age.count() <= 0)
break;
}
}
if (age.count() <= 0)
{
// the oldest chunk (top of the stream) can be played in this iteration
// e.g. age = -20ms (=> should be played in 20ms)
// and the current chunk duration is 50ms, so we need to play 20ms silence (as we don't have data)
// and can play 30ms of the stream
uint32_t silent_frames = static_cast<uint32_t>(-chunk_->format.nsRate() * std::chrono::duration_cast<cs::nsec>(age).count());
bool result = (silent_frames <= frames);
silent_frames = std::min(silent_frames, frames);
LOG(DEBUG, LOG_TAG) << "Silent frames: " << silent_frames << ", frames: " << frames
<< ", age: " << std::chrono::duration_cast<cs::usec>(age).count() / 1000. << "\n";
getSilentPlayerChunk(outputBuffer, silent_frames);
getNextPlayerChunk((char*)outputBuffer + (chunk_->format.frameSize() * silent_frames), frames - silent_frames);
if (result)
{
hard_sync_ = false;
resetBuffers();
}
return true;
}
return false;
}
}
// sample rate correction
// framesCorrection = number of frames to be read more or less to get in-sync
int32_t framesCorrection = 0;
if (correctAfterXFrames_ != 0)
{
playedFrames_ += frames;
if (playedFrames_ >= (uint32_t)abs(correctAfterXFrames_))
{
framesCorrection = static_cast<int32_t>(playedFrames_) / correctAfterXFrames_;
playedFrames_ %= abs(correctAfterXFrames_);
}
}
cs::usec age = std::chrono::duration_cast<cs::usec>(TimeProvider::serverNow() - getNextPlayerChunk(outputBuffer, frames, framesCorrection) - bufferMs_ +
outputBufferDacTime);
setRealSampleRate(format_.rate());
// check if we need a hard sync
if (buffer_.full() && (cs::usec(abs(median_)) > cs::msec(2)) && (cs::abs(age) > cs::usec(500)))
{
LOG(INFO, LOG_TAG) << "pBuffer->full() && (abs(median_) > 2): " << median_ << "\n";
hard_sync_ = true;
}
else if (shortBuffer_.full() && (cs::usec(abs(shortMedian_)) > cs::msec(5)) && (cs::abs(age) > cs::usec(500)))
{
LOG(INFO, LOG_TAG) << "pShortBuffer->full() && (abs(shortMedian_) > 5): " << shortMedian_ << "\n";
hard_sync_ = true;
}
else if (miniBuffer_.full() && (cs::usec(abs(miniBuffer_.median())) > cs::msec(50)) && (cs::abs(age) > cs::usec(500)))
{
LOG(INFO, LOG_TAG) << "pMiniBuffer->full() && (abs(pMiniBuffer->mean()) > 50): " << miniBuffer_.median() << "\n";
hard_sync_ = true;
}
else if (cs::abs(age) > 500ms)
{
LOG(INFO, LOG_TAG) << "abs(age > 500): " << cs::abs(age).count() << "\n";
hard_sync_ = true;
}
else if (shortBuffer_.full())
{
// No hard sync needed
// Check if we need a samplerate correction (change playback speed (soft sync))
auto miniMedian = miniBuffer_.median();
if ((cs::usec(shortMedian_) > kCorrectionBegin) && (cs::usec(miniMedian) > cs::usec(50)) && (cs::usec(age) > cs::usec(50)))
{
double rate = (shortMedian_ / 100) * 0.00005;
rate = 1.0 - std::min(rate, 0.0005);
// LOG(INFO, LOG_TAG) << "Rate: " << rate << "\n";
// we are late (age > 0), this means we are not playing fast enough
// => the real sample rate seems to be lower, we have to drop some frames
setRealSampleRate(format_.rate() * rate); // 0.9999);
}
else if ((cs::usec(shortMedian_) < -kCorrectionBegin) && (cs::usec(miniMedian) < -cs::usec(50)) && (cs::usec(age) < -cs::usec(50)))
{
double rate = (-shortMedian_ / 100) * 0.00005;
rate = 1.0 + std::min(rate, 0.0005);
// LOG(INFO, LOG_TAG) << "Rate: " << rate << "\n";
// we are early (age > 0), this means we are playing too fast
// => the real sample rate seems to be higher, we have to insert some frames
setRealSampleRate(format_.rate() * rate); // 1.0001);
}
}
updateBuffers(age.count());
// update median_ and shortMedian_ and print sync stats
if (now != lastUpdate_)
{
lastUpdate_ = now;
median_ = buffer_.median();
shortMedian_ = shortBuffer_.median();
LOG(DEBUG, "Stats") << "Chunk: " << age.count() / 100 << "\t" << miniBuffer_.median() / 100 << "\t" << shortMedian_ / 100 << "\t" << median_ / 100
<< "\t" << buffer_.size() << "\t" << cs::duration<cs::msec>(outputBufferDacTime) << "\t" << frame_delta_ << "\n";
frame_delta_ = 0;
}
return (abs(cs::duration<cs::msec>(age)) < 500);
}
catch (int e)
{
LOG(INFO, LOG_TAG) << "Exception: " << e << "\n";
hard_sync_ = true;
return false;
}
}
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