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livetrax/libs/backends/alsa/alsa_slave.cc

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/*
* Copyright (C) 2017 Paul Davis <paul@linuxaudiosystems.com>
* Copyright (C) 2017 Robin Gareus <robin@gareus.org>
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <cmath>
#include <glibmm.h>
#include "pbd/compose.h"
#include "pbd/error.h"
#include "pbd/pthread_utils.h"
#include "alsa_slave.h"
#include "pbd/i18n.h"
using namespace ARDOUR;
AlsaAudioSlave::AlsaAudioSlave (
const char *play_name,
const char *capt_name,
unsigned int master_rate,
unsigned int master_samples_per_period,
unsigned int slave_rate,
unsigned int slave_samples_per_period,
unsigned int periods_per_cycle)
: _pcmi (play_name, capt_name, 0, slave_rate, slave_samples_per_period, periods_per_cycle, 2, /* Alsa_pcmi::DEBUG_ALL */ 0)
, _run (false)
, _active (false)
, _samples_since_dll_reset (0)
, _ratio (1.0)
, _slave_speed (1.0)
, _rb_capture (4 * /* AlsaAudioBackend::_max_buffer_size */ 8192 * _pcmi.ncapt ())
, _rb_playback (4 * /* AlsaAudioBackend::_max_buffer_size */ 8192 * _pcmi.nplay ())
, _samples_per_period (master_samples_per_period)
, _capt_buff (0)
, _play_buff (0)
, _src_buff (0)
{
_draining.store (1);
if (0 != _pcmi.state()) {
return;
}
/* from alsa-slave to master */
_ratio = (double) master_rate / (double) _pcmi.fsamp();
#ifndef NDEBUG
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fprintf (stdout, " --[[ ALSA Slave %s/%s ratio: %.4f\n",
capt_name ? capt_name : "-",
play_name ? play_name : "-",
_ratio);
_pcmi.printinfo ();
fprintf (stdout, " --]]\n");
#endif
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if (_pcmi.ncapt () > 0) {
_src_capt.setup (_ratio, _pcmi.ncapt (), /*quality*/ 32); // save capture to master
_src_capt.set_rrfilt (100);
_capt_buff = (float*) malloc (sizeof(float) * _pcmi.ncapt () * _samples_per_period);
}
if (_pcmi.nplay () > 0) {
_src_play.setup (1.0 / _ratio, _pcmi.nplay (), /*quality*/ 32); // master to slave play
_src_play.set_rrfilt (100);
_play_buff = (float*) malloc (sizeof(float) * _pcmi.nplay () * _samples_per_period);
}
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if (_pcmi.nplay () > 0 || _pcmi.ncapt () > 0) {
_src_buff = (float*) malloc (sizeof(float) * std::max (_pcmi.nplay (), _pcmi.ncapt ()));
}
}
AlsaAudioSlave::~AlsaAudioSlave ()
{
stop ();
free (_capt_buff);
free (_play_buff);
free (_src_buff);
}
void
AlsaAudioSlave::reset_resampler (ArdourZita::VResampler& src)
{
src.reset ();
src.inp_count = src.inpsize () - 1;
src.out_count = 200000;
src.process ();
}
bool
AlsaAudioSlave::start ()
{
if (_run) {
return false;
}
_run = true;
if (pbd_realtime_pthread_create (PBD_SCHED_FIFO, PBD_RT_PRI_MAIN, PBD_RT_STACKSIZE_HELP,
&_thread, _process_thread, this))
{
if (pbd_pthread_create (PBD_RT_STACKSIZE_HELP, &_thread, _process_thread, this)) {
_run = false;
PBD::error << _("AlsaAudioBackend: failed to create slave process thread.") << endmsg;
return false;
}
}
int timeout = 5000;
while (!_active && --timeout > 0) { Glib::usleep (1000); }
if (timeout == 0 || !_active) {
_run = false;
PBD::error << _("AlsaAudioBackend: failed to start slave process thread.") << endmsg;
return false;
}
return true;
}
void
AlsaAudioSlave::stop ()
{
void *status;
if (!_run) {
return;
}
_run = false;
if (pthread_join (_thread, &status)) {
PBD::error << _("AlsaAudioBackend: slave failed to terminate properly.") << endmsg;
}
_pcmi.pcm_stop ();
}
void*
AlsaAudioSlave::_process_thread (void* arg)
{
AlsaAudioSlave* aas = static_cast<AlsaAudioSlave*> (arg);
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pthread_set_name ("AlsaAudioSlave");
return aas->process_thread ();
}
void*
AlsaAudioSlave::process_thread ()
{
_active = true;
bool reset_dll = true;
int last_n_periods = 0;
int no_proc_errors = 0;
const int bailout = 2 * _pcmi.fsamp () / _pcmi.fsize ();
double dll_dt = (double) _pcmi.fsize () / (double)_pcmi.fsamp ();
double dll_w1 = 2 * M_PI * 0.1 * dll_dt;
double dll_w2 = dll_w1 * dll_w1;
const double sr_norm = 1e-6 * (double) _pcmi.fsamp () / (double) _pcmi.fsize ();
_pcmi.pcm_start ();
while (_run) {
bool xrun = false;
long nr = _pcmi.pcm_wait ();
/* update DLL */
uint64_t clock0 = g_get_monotonic_time();
if (reset_dll || last_n_periods != 1) {
reset_dll = false;
dll_dt = 1e6 * (double) _pcmi.fsize () / (double) _pcmi.fsamp();
_t0 = clock0;
_t1 = clock0 + dll_dt;
_samples_since_dll_reset = 0;
} else {
const double er = clock0 - _t1;
_t0 = _t1;
_t1 = _t1 + dll_w1 * er + dll_dt;
dll_dt += dll_w2 * er;
_samples_since_dll_reset += _pcmi.fsize ();
}
_slave_speed = (_t1 - _t0) * sr_norm; // XXX atomic
if (_pcmi.state () > 0) {
++no_proc_errors;
xrun = true;
}
if (_pcmi.state () < 0) {
PBD::error << _("AlsaAudioBackend: Slave I/O error.") << endmsg;
break;
}
if (no_proc_errors > bailout) {
PBD::error << _("AlsaAudioBackend: Slave terminated due to continuous xruns.") << endmsg;
break;
}
const size_t spp = _pcmi.fsize ();
const bool drain = _draining.load ();
last_n_periods = 0;
while (nr >= (long)spp) {
no_proc_errors = 0;
_pcmi.capt_init (spp);
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if (drain || _pcmi.ncapt () == 0) {
/* do nothing */
} else if (_rb_capture.write_space () >= _pcmi.ncapt () * spp) {
#if 0 // failsafe: write interleave sample by sample
for (uint32_t s = 0; s < spp; ++s) {
for (uint32_t c = 0; c < _pcmi.ncapt (); ++c) {
float d;
_pcmi.capt_chan (c, &d, 1);
_rb_capture.write (&d, 1);
}
}
#else
unsigned int nchn = _pcmi.ncapt ();
PBD::RingBuffer<float>::rw_vector vec;
_rb_capture.get_write_vector (&vec);
if (vec.len[0] >= nchn * spp) {
for (uint32_t c = 0; c < nchn; ++c) {
_pcmi.capt_chan (c, vec.buf[0] + c, spp, nchn);
}
} else {
uint32_t c;
/* first copy continuous area */
uint32_t k = vec.len[0] / nchn;
for (c = 0; c < nchn; ++c) {
_pcmi.capt_chan (c, vec.buf[0] + c, k, nchn);
}
/* possible samples at end of first buffer chunk,
* incomplete audio-sample */
uint32_t s = vec.len[0] - k * nchn;
assert (s < nchn);
for (c = 0; c < s; ++c) {
_pcmi.capt_chan (c, vec.buf[0] + k * nchn + c, 1, nchn);
}
/* cont'd audio-sample at second ringbuffer chunk */
for (; c < nchn; ++c) {
_pcmi.capt_chan (c, vec.buf[1] + c - s, spp - k, nchn);
}
/* remaining data in 2nd area */
for (c = 0; c < s; ++c) {
_pcmi.capt_chan (c, vec.buf[1] + c + nchn - s, spp - k, nchn);
}
}
_rb_capture.increment_write_idx (spp * nchn);
#endif
} else {
_draining.store (1);
}
_pcmi.capt_done (spp);
if (drain) {
_rb_playback.increment_read_idx (_rb_playback.read_space ());
}
_pcmi.play_init (spp);
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if (_pcmi.nplay () == 0) {
/* relax */
}
else if (_rb_playback.read_space () >= _pcmi.nplay () * spp) {
#if 0 // failsafe: read sample by sample de-interleave
for (uint32_t s = 0; s < spp; ++s) {
for (uint32_t c = 0; c < _pcmi.nplay (); ++c) {
float d;
_rb_playback.read (&d, 1);
_pcmi.play_chan (c, (const float*)&d, 1);
}
}
#else
unsigned int nchn = _pcmi.nplay ();
PBD::RingBuffer<float>::rw_vector vec;
_rb_playback.get_read_vector (&vec);
if (vec.len[0] >= nchn * spp) {
for (uint32_t c = 0; c < nchn; ++c) {
_pcmi.play_chan (c, vec.buf[0] + c, spp, nchn);
}
} else {
uint32_t c;
uint32_t k = vec.len[0] / nchn;
for (c = 0; c < nchn; ++c) {
_pcmi.play_chan (c, vec.buf[0] + c, k, nchn);
}
uint32_t s = vec.len[0] - k * nchn;
assert (s < nchn);
for (c = 0; c < s; ++c) {
_pcmi.play_chan (c, vec.buf[0] + k * nchn + c, 1, nchn);
}
for (; c < nchn; ++c) {
_pcmi.play_chan (c, vec.buf[1] + c - s, spp - k, nchn);
}
for (c = 0; c < s; ++c) {
_pcmi.play_chan (c, vec.buf[1] + c + nchn - s, spp - k, nchn);
}
}
_rb_playback.increment_read_idx (spp * nchn);
#endif
} else {
if (!drain) {
#ifndef NDEBUG
printf ("Slave Process: Playback Buffer Underflow, have %u want %lu\n", _rb_playback.read_space (), _pcmi.nplay () * spp); // XXX DEBUG
#endif
_play_latency += spp * _ratio;
update_latencies (_play_latency, _capt_latency);
}
/* silence outputs */
for (uint32_t c = 0; c < _pcmi.nplay (); ++c) {
_pcmi.clear_chan (c, spp);
}
}
_pcmi.play_done (spp);
nr -= spp;
++last_n_periods;
}
if (xrun && (_pcmi.capt_xrun() > 0 || _pcmi.play_xrun() > 0)) {
reset_dll = true;
_samples_since_dll_reset = 0;
_draining.store (1);
}
}
_pcmi.pcm_stop ();
_active = false;
if (_run) {
Halted (); /* Emit Signal */
}
return 0;
}
void
AlsaAudioSlave::cycle_start (double tme, double mst_speed, bool drain)
{
//printf ("SRC %f / %f = %f\n", mst_speed, _slave_speed, mst_speed / _slave_speed);
//printf ("DRIFT (mst) %11.1f - (slv) %11.1f = %.1f us = %.1f spl\n", tme, _t0, tme - _t0, (tme - _t0) * _pcmi.fsamp () * 1e-6);
//printf ("Slave capt: %u play: %u\n", _rb_capture.read_space (), _rb_playback.read_space ());
// TODO LPF filter ratios, atomic _slave_speed
const double slave_speed = _slave_speed;
_src_capt.set_rratio (mst_speed / slave_speed);
_src_play.set_rratio (slave_speed / mst_speed);
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if (_capt_buff) {
memset (_capt_buff, 0, sizeof(float) * _pcmi.ncapt () * _samples_per_period);
}
if (drain) {
_draining.store (1);
return;
}
if (_draining.load ()) {
_rb_capture.increment_read_idx (_rb_capture.read_space());
return;
}
/* resample slave capture data from ringbuffer */
unsigned int nchn = _pcmi.ncapt ();
_src_capt.out_count = _samples_per_period;
_src_capt.out_data = _capt_buff;
/* estimate required samples */
const double rratio = _ratio * mst_speed / slave_speed;
if (_rb_capture.read_space() < ceil (nchn * _samples_per_period / rratio)) {
#ifndef NDEBUG
printf ("--- UNDERFLOW --- have %u want %.1f\n", _rb_capture.read_space(), ceil (nchn * _samples_per_period / rratio)); // XXX DEBUG
#endif
_capt_latency += _samples_per_period;
update_latencies (_play_latency, _capt_latency);
return;
}
bool underflow = false;
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while (_src_capt.out_count && _active && nchn > 0) {
if (_rb_capture.read_space() < nchn) {
underflow = true;
break;
}
unsigned int n;
PBD::RingBuffer<float>::rw_vector vec;
_rb_capture.get_read_vector (&vec);
if (vec.len[0] < nchn) {
_rb_capture.read (_src_buff, nchn);
_src_capt.inp_count = 1;
_src_capt.inp_data = _src_buff;
_src_capt.process ();
} else {
_src_capt.inp_count = n = vec.len[0] / nchn;
_src_capt.inp_data = vec.buf[0];
_src_capt.process ();
n -= _src_capt.inp_count;
_rb_capture.increment_read_idx (n * _pcmi.ncapt ());
}
}
if (underflow) {
#ifndef NDEBUG
std::cerr << "ALSA Slave: Capture Ringbuffer Underflow\n"; // XXX DEBUG
#endif
_draining.store (1);
}
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if ((!_active || underflow) && _capt_buff) {
memset (_capt_buff, 0, sizeof(float) * _pcmi.ncapt () * _samples_per_period);
}
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if (_play_buff) {
memset (_play_buff, 0, sizeof(float) * _pcmi.nplay () * _samples_per_period);
}
}
void
AlsaAudioSlave::cycle_end ()
{
bool drain_done = false;
bool overflow = false;
if (_draining.load ()) {
if (_rb_capture.read_space() == 0 && _rb_playback.read_space() == 0 && _samples_since_dll_reset > _pcmi.fsamp ()) {
reset_resampler (_src_capt);
reset_resampler (_src_play);
memset (_src_buff, 0, sizeof (float) * _pcmi.nplay());
/* prefill ringbuffers, resampler variance */
for (int i = 0; i < 16; ++i) {
_rb_playback.write (_src_buff, _pcmi.nplay());
}
memset (_src_buff, 0, sizeof (float) * _pcmi.ncapt());
// It's safe to write here, process-thread NO-OPs while draining.
for (int i = 0; i < 16; ++i) {
_rb_capture.write (_src_buff, _pcmi.ncapt());
}
_capt_latency = 16;
_play_latency = 16 + _ratio * _pcmi.fsize () * (_pcmi.play_nfrag () - 1);
update_latencies (_play_latency, _capt_latency);
drain_done = true;
} else {
return;
}
}
/* resample collected playback data into ringbuffer */
unsigned int nchn = _pcmi.nplay ();
_src_play.inp_count = _samples_per_period;
_src_play.inp_data = _play_buff;
while (_src_play.inp_count && _active && nchn > 0) {
unsigned int n;
PBD::RingBuffer<float>::rw_vector vec;
_rb_playback.get_write_vector (&vec);
if (vec.len[0] < nchn) {
_src_play.out_count = 1;
_src_play.out_data = _src_buff;
_src_play.process ();
if (_rb_playback.write_space() < nchn) {
overflow = true;
break;
} else if (_src_play.out_count == 0) {
_rb_playback.write (_src_buff, nchn);
}
} else {
_src_play.out_count = n = vec.len[0] / nchn;
_src_play.out_data = vec.buf[0];
_src_play.process ();
n -= _src_play.out_count;
if (_rb_playback.write_space() < n * nchn) {
overflow = true;
break;
}
_rb_playback.increment_write_idx (n * nchn);
}
}
if (overflow) {
#ifndef NDEBUG
std::cerr << "ALSA Slave: Playback Ringbuffer Overflow\n"; // XXX DEBUG
#endif
_draining.store (1);
return;
}
if (drain_done) {
_draining.store (0);
}
}
void
AlsaAudioSlave::freewheel (bool onoff)
{
if (onoff) {
_draining.store (1);
}
}
/* master read slave's capture.
* resampled at cycle_start, before master can call this
*/
uint32_t
AlsaAudioSlave::capt_chan (uint32_t chn, float* dst, uint32_t n_samples)
{
uint32_t nchn = _pcmi.ncapt ();
assert (chn < nchn && n_samples == _samples_per_period);
float* src = &_capt_buff[chn];
for (uint32_t s = 0; s < n_samples; ++s) {
dst[s] = src[s * nchn];
}
return n_samples;
}
/* write from master to slave output,
* resampled at cycle_end, after master called this.
*/
uint32_t
AlsaAudioSlave::play_chan (uint32_t chn, float* src, uint32_t n_samples)
{
uint32_t nchn = _pcmi.nplay ();
assert (chn < nchn && n_samples == _samples_per_period);
float* dst = &_play_buff[chn];
for (uint32_t s = 0; s < n_samples; ++s) {
dst[s * nchn] = src[s];
}
return n_samples;
}