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Diffstat (limited to 'tools/zalsa/alsathread.cc')
| -rw-r--r-- | tools/zalsa/alsathread.cc | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/tools/zalsa/alsathread.cc b/tools/zalsa/alsathread.cc new file mode 100644 index 00000000..1ce5dd93 --- /dev/null +++ b/tools/zalsa/alsathread.cc @@ -0,0 +1,218 @@ +// ---------------------------------------------------------------------------- +// +// Copyright (C) 2012-2018 Fons Adriaensen <fons@linuxaudio.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 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/>. +// +// ---------------------------------------------------------------------------- + + +#include <stdlib.h> +#include <string.h> +#include <stdio.h> +#include <math.h> +#include "alsathread.h" +#include "timers.h" + + +Alsathread::Alsathread (Alsa_pcmi *alsadev, int mode) : + _alsadev (alsadev ), + _mode (mode), + _state (INIT), + _fsize (alsadev->fsize ()), + _audioq (0), + _commq (0), + _alsaq (0) +{ + // Compute DLL filter coefficients. + _dt = (double) _fsize / _alsadev->fsamp (); + _w1 = 2 * M_PI * 0.1 * _dt; + _w2 = _w1 * _w1; + _w1 *= 1.6; +} + + +Alsathread::~Alsathread (void) +{ + _alsadev->pcm_stop (); +} + + +int Alsathread::start (Lfq_audio *audioq, Lfq_int32 *commq, Lfq_adata *alsaq, int rtprio) +{ + // Start the ALSA thread. + _audioq = audioq; + _commq = commq; + _alsaq = alsaq; + _state = WAIT; + if (thr_start (SCHED_FIFO, rtprio, 0x10000)) return 1; + return 0; +} + + +void Alsathread::send (int k, double t) +{ + Adata *D; + + // Send (state, frame count, timestamp) to Jack thread. + if (_alsaq->wr_avail ()) + { + D = _alsaq->wr_datap (); + D->_state = _state; + D->_nsamp = k; + D->_timer = t; + _alsaq->wr_commit (); + } +} + + +// The following two functions transfer data between the audio queue +// and the ALSA device. Note that we do *not* check the queue's fill +// state, and it may overrun or underrun. It actually will in the first +// few iterations and in error conditions. This is entirely intentional. +// The queue keeps correct read and write counters even in that case, +// and the main control loop and error recovery depend on it working +// and being used in this way. + +int Alsathread::capture (void) +{ + int c, n, k; + float *p; + + // Start reading from ALSA device. + _alsadev->capt_init (_fsize); + if (_state == PROC) + { + // Input frames from the ALSA device to the audio queue. + // The outer loop takes care of wraparound. + for (n = _fsize; n; n -= k) + { + p = _audioq->wr_datap (); // Audio queue write pointer. + k = _audioq->wr_linav (); // Number of frames that can be + if (k > n) k = n; // written without wraparound. + for (c = 0; c < _audioq->nchan (); c++) + { + // Copy and interleave one channel. + _alsadev->capt_chan (c, p + c, k, _audioq->nchan ()); + } + _audioq->wr_commit (k); // Update audio queue state. + } + } + // Finish reading from ALSA device. + _alsadev->capt_done (_fsize); + return _fsize; +} + + +int Alsathread::playback (void) +{ + int c, n, k; + float *p; + + // Start writing to ALSA device. + _alsadev->play_init (_fsize); + c = 0; + if (_state == PROC) + { + // Output frames from the audio queue to the ALSA device. + // The outer loop takes care of wraparound. + for (n = _fsize; n; n -= k) + { + p = _audioq->rd_datap (); // Audio queue read pointer. + k = _audioq->rd_linav (); // Number of frames that can + if (k > n) k = n; // be read without wraparound. + for (c = 0; c < _audioq->nchan (); c++) + { + // De-interleave and copy one channel. + _alsadev->play_chan (c, p + c, k, _audioq->nchan ()); + } + _audioq->rd_commit (k); // Update audio queue state. + } + } + // Clear all or remaining channels. + while (c < _alsadev->nplay ()) _alsadev->clear_chan (c++, _fsize); + // Finish writing to ALSA device. + _alsadev->play_done (_fsize); + return _fsize; +} + + +void Alsathread::thr_main (void) +{ + int na, nu; + double tw, er; + + _alsadev->pcm_start (); + while (_state != TERM) + { + // Wait for next cycle, then take timestamp. + na = _alsadev->pcm_wait (); + + tw = tjack (jack_get_time ()); + // Check for errors - requires restart. + if (_alsadev->state () && (na == 0)) + { + _state = WAIT; + send (0, 0); + usleep (10000); + continue; + } + + // Check for commands from the Jack thread. + if (_commq->rd_avail ()) + { + _state = _commq->rd_int32 (); + if (_state == PROC) _first = true; + if (_state == TERM) send (0, 0); + } + + // We could have more than one period. + nu = 0; + while (na >= _fsize) + { + // Transfer frames. + if (_mode == PLAY) nu += playback (); + else nu += capture (); + // Update loop condition. + na -= _fsize; + // Run the DLL if in PROC state. + if (_state == PROC) + { + if (_first) + { + // Init DLL in first iteration. + _first = false; + _dt = (double) _fsize / _alsadev->fsamp (); + _t0 = tw; + _t1 = tw + _dt; + } + else + { + // Update the DLL. + // If we have more than one period, use + // the time error only for the last one. + if (na >= _fsize) er = 0; + else er = tjack_diff (tw, _t1); + _t0 = _t1; + _t1 = tjack_diff (_t1 + _dt + _w1 * er, 0.0); + _dt += _w2 * er; + } + } + } + + // Send number of frames used and timestamp to Jack thread. + if (_state == PROC) send (nu, _t1); + } + _alsadev->pcm_stop (); +} |