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ALSA project - the C library reference
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ALSA project - the C library reference
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/* * Latency test program * * Author: Jaroslav Kysela <perex@perex.cz> * * Author of bandpass filter sweep effect: * Maarten de Boer <mdeboer@iua.upf.es> * * This small demo program can be used for measuring latency between * capture and playback. This latency is measured from driver (diff when * playback and capture was started). Scheduler is set to SCHED_RR. * * * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sched.h> #include <errno.h> #include <getopt.h> #include "../include/asoundlib.h" #include <sys/time.h> #include <math.h> char *pdevice = "hw:0,0"; char *cdevice = "hw:0,0"; snd_pcm_format_t format = SND_PCM_FORMAT_S16_LE; int rate = 22050; int channels = 2; int buffer_size = 0; /* auto */ int period_size = 0; /* auto */ int latency_min = 32; /* in frames / 2 */ int latency_max = 2048; /* in frames / 2 */ int loop_sec = 30; /* seconds */ int block = 0; /* block mode */ int use_poll = 0; int resample = 1; unsigned long loop_limit; snd_output_t *output = NULL; int setparams_stream(snd_pcm_t *handle, snd_pcm_hw_params_t *params, const char *id) { int err; unsigned int rrate; err = snd_pcm_hw_params_any(handle, params); if (err < 0) { printf("Broken configuration for %s PCM: no configurations available: %s\n", snd_strerror(err), id); return err; } err = snd_pcm_hw_params_set_rate_resample(handle, params, resample); if (err < 0) { printf("Resample setup failed for %s (val %i): %s\n", id, resample, snd_strerror(err)); return err; } err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED); if (err < 0) { printf("Access type not available for %s: %s\n", id, snd_strerror(err)); return err; } err = snd_pcm_hw_params_set_format(handle, params, format); if (err < 0) { printf("Sample format not available for %s: %s\n", id, snd_strerror(err)); return err; } err = snd_pcm_hw_params_set_channels(handle, params, channels); if (err < 0) { printf("Channels count (%i) not available for %s: %s\n", channels, id, snd_strerror(err)); return err; } rrate = rate; err = snd_pcm_hw_params_set_rate_near(handle, params, &rrate, 0); if (err < 0) { printf("Rate %iHz not available for %s: %s\n", rate, id, snd_strerror(err)); return err; } if ((int)rrate != rate) { printf("Rate doesn't match (requested %iHz, get %iHz)\n", rate, err); return -EINVAL; } return 0; } int setparams_bufsize(snd_pcm_t *handle, snd_pcm_hw_params_t *params, snd_pcm_hw_params_t *tparams, snd_pcm_uframes_t bufsize, const char *id) { int err; snd_pcm_uframes_t periodsize; snd_pcm_hw_params_copy(params, tparams); periodsize = bufsize * 2; err = snd_pcm_hw_params_set_buffer_size_near(handle, params, &periodsize); if (err < 0) { printf("Unable to set buffer size %li for %s: %s\n", bufsize * 2, id, snd_strerror(err)); return err; } if (period_size > 0) periodsize = period_size; else periodsize /= 2; err = snd_pcm_hw_params_set_period_size_near(handle, params, &periodsize, 0); if (err < 0) { printf("Unable to set period size %li for %s: %s\n", periodsize, id, snd_strerror(err)); return err; } return 0; } int setparams_set(snd_pcm_t *handle, snd_pcm_hw_params_t *params, snd_pcm_sw_params_t *swparams, const char *id) { int err; snd_pcm_uframes_t val; err = snd_pcm_hw_params(handle, params); if (err < 0) { printf("Unable to set hw params for %s: %s\n", id, snd_strerror(err)); return err; } err = snd_pcm_sw_params_current(handle, swparams); if (err < 0) { printf("Unable to determine current swparams for %s: %s\n", id, snd_strerror(err)); return err; } err = snd_pcm_sw_params_set_start_threshold(handle, swparams, 0x7fffffff); if (err < 0) { printf("Unable to set start threshold mode for %s: %s\n", id, snd_strerror(err)); return err; } if (!block) val = 4; else snd_pcm_hw_params_get_period_size(params, &val, NULL); err = snd_pcm_sw_params_set_avail_min(handle, swparams, val); if (err < 0) { printf("Unable to set avail min for %s: %s\n", id, snd_strerror(err)); return err; } err = snd_pcm_sw_params(handle, swparams); if (err < 0) { printf("Unable to set sw params for %s: %s\n", id, snd_strerror(err)); return err; } return 0; } int setparams(snd_pcm_t *phandle, snd_pcm_t *chandle, int *bufsize) { int err, last_bufsize = *bufsize; snd_pcm_hw_params_t *pt_params, *ct_params; /* templates with rate, format and channels */ snd_pcm_hw_params_t *p_params, *c_params; snd_pcm_sw_params_t *p_swparams, *c_swparams; snd_pcm_uframes_t p_size, c_size, p_psize, c_psize; unsigned int p_time, c_time; snd_pcm_hw_params_alloca(&p_params); snd_pcm_hw_params_alloca(&c_params); snd_pcm_hw_params_alloca(&pt_params); snd_pcm_hw_params_alloca(&ct_params); snd_pcm_sw_params_alloca(&p_swparams); snd_pcm_sw_params_alloca(&c_swparams); if ((err = setparams_stream(phandle, pt_params, "playback")) < 0) { printf("Unable to set parameters for playback stream: %s\n", snd_strerror(err)); exit(0); } if ((err = setparams_stream(chandle, ct_params, "capture")) < 0) { printf("Unable to set parameters for playback stream: %s\n", snd_strerror(err)); exit(0); } if (buffer_size > 0) { *bufsize = buffer_size; goto __set_it; } __again: if (buffer_size > 0) return -1; if (last_bufsize == *bufsize) *bufsize += 4; last_bufsize = *bufsize; if (*bufsize > latency_max) return -1; __set_it: if ((err = setparams_bufsize(phandle, p_params, pt_params, *bufsize, "playback")) < 0) { printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err)); exit(0); } if ((err = setparams_bufsize(chandle, c_params, ct_params, *bufsize, "capture")) < 0) { printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err)); exit(0); } snd_pcm_hw_params_get_period_size(p_params, &p_psize, NULL); if (p_psize > (unsigned int)*bufsize) *bufsize = p_psize; snd_pcm_hw_params_get_period_size(c_params, &c_psize, NULL); if (c_psize > (unsigned int)*bufsize) *bufsize = c_psize; snd_pcm_hw_params_get_period_time(p_params, &p_time, NULL); snd_pcm_hw_params_get_period_time(c_params, &c_time, NULL); if (p_time != c_time) goto __again; snd_pcm_hw_params_get_buffer_size(p_params, &p_size); if (p_psize * 2 < p_size) goto __again; snd_pcm_hw_params_get_buffer_size(c_params, &c_size); if (c_psize * 2 < c_size) goto __again; if ((err = setparams_set(phandle, p_params, p_swparams, "playback")) < 0) { printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err)); exit(0); } if ((err = setparams_set(chandle, c_params, c_swparams, "capture")) < 0) { printf("Unable to set sw parameters for playback stream: %s\n", snd_strerror(err)); exit(0); } if ((err = snd_pcm_prepare(phandle)) < 0) { printf("Prepare error: %s\n", snd_strerror(err)); exit(0); } snd_pcm_dump(phandle, output); snd_pcm_dump(chandle, output); fflush(stdout); return 0; } void showstat(snd_pcm_t *handle, size_t frames) { int err; snd_pcm_status_t *status; snd_pcm_status_alloca(&status); if ((err = snd_pcm_status(handle, status)) < 0) { printf("Stream status error: %s\n", snd_strerror(err)); exit(0); } printf("*** frames = %li ***\n", (long)frames); snd_pcm_status_dump(status, output); } void showlatency(size_t latency) { double d; latency *= 2; d = (double)latency / (double)rate; printf("Trying latency %li frames, %.3fus, %.6fms (%.4fHz)\n", (long)latency, d * 1000000, d * 1000, (double)1 / d); } void showinmax(size_t in_max) { double d; printf("Maximum read: %li frames\n", (long)in_max); d = (double)in_max / (double)rate; printf("Maximum read latency: %.3fus, %.6fms (%.4fHz)\n", d * 1000000, d * 1000, (double)1 / d); } void gettimestamp(snd_pcm_t *handle, snd_timestamp_t *timestamp) { int err; snd_pcm_status_t *status; snd_pcm_status_alloca(&status); if ((err = snd_pcm_status(handle, status)) < 0) { printf("Stream status error: %s\n", snd_strerror(err)); exit(0); } snd_pcm_status_get_trigger_tstamp(status, timestamp); } void setscheduler(void) { struct sched_param sched_param; if (sched_getparam(0, &sched_param) < 0) { printf("Scheduler getparam failed...\n"); return; } sched_param.sched_priority = sched_get_priority_max(SCHED_RR); if (!sched_setscheduler(0, SCHED_RR, &sched_param)) { printf("Scheduler set to Round Robin with priority %i...\n", sched_param.sched_priority); fflush(stdout); return; } printf("!!!Scheduler set to Round Robin with priority %i FAILED!!!\n", sched_param.sched_priority); } long timediff(snd_timestamp_t t1, snd_timestamp_t t2) { signed long l; t1.tv_sec -= t2.tv_sec; l = (signed long) t1.tv_usec - (signed long) t2.tv_usec; if (l < 0) { t1.tv_sec--; l = -l; l %= 1000000; } return (t1.tv_sec * 1000000) + l; } long readbuf(snd_pcm_t *handle, char *buf, long len, size_t *frames, size_t *max) { long r; if (!block) { do { r = snd_pcm_readi(handle, buf, len); } while (r == -EAGAIN); if (r > 0) { *frames += r; if ((long)*max < r) *max = r; } // printf("read = %li\n", r); } else { int frame_bytes = (snd_pcm_format_width(format) / 8) * channels; do { r = snd_pcm_readi(handle, buf, len); if (r > 0) { buf += r * frame_bytes; len -= r; *frames += r; if ((long)*max < r) *max = r; } // printf("r = %li, len = %li\n", r, len); } while (r >= 1 && len > 0); } // showstat(handle, 0); return r; } long writebuf(snd_pcm_t *handle, char *buf, long len, size_t *frames) { long r; while (len > 0) { r = snd_pcm_writei(handle, buf, len); if (r == -EAGAIN) continue; // printf("write = %li\n", r); if (r < 0) return r; // showstat(handle, 0); buf += r * 4; len -= r; *frames += r; } return 0; } #define FILTERSWEEP_LFO_CENTER 2000. #define FILTERSWEEP_LFO_DEPTH 1800. #define FILTERSWEEP_LFO_FREQ 0.2 #define FILTER_BANDWIDTH 50 /* filter the sweep variables */ float lfo,dlfo,fs,fc,BW,C,D,a0,a1,a2,b1,b2,*x[3],*y[3]; void applyeffect(char* buffer,int r) { short* samples = (short*) buffer; int i; for (i=0;i<r;i++) { int chn; fc = sin(lfo)*FILTERSWEEP_LFO_DEPTH+FILTERSWEEP_LFO_CENTER; lfo += dlfo; if (lfo>2.*M_PI) lfo -= 2.*M_PI; C = 1./tan(M_PI*BW/fs); D = 2.*cos(2*M_PI*fc/fs); a0 = 1./(1.+C); a1 = 0; a2 = -a0; b1 = -C*D*a0; b2 = (C-1)*a0; for (chn=0;chn<channels;chn++) { x[chn][2] = x[chn][1]; x[chn][1] = x[chn][0]; y[chn][2] = y[chn][1]; y[chn][1] = y[chn][0]; x[chn][0] = samples[i*channels+chn]; y[chn][0] = a0*x[chn][0] + a1*x[chn][1] + a2*x[chn][2] - b1*y[chn][1] - b2*y[chn][2]; samples[i*channels+chn] = y[chn][0]; } } } void help(void) { int k; printf( "Usage: latency [OPTION]... [FILE]...\n" "-h,--help help\n" "-P,--pdevice playback device\n" "-C,--cdevice capture device\n" "-m,--min minimum latency in frames\n" "-M,--max maximum latency in frames\n" "-F,--frames frames to transfer\n" "-f,--format sample format\n" "-c,--channels channels\n" "-r,--rate rate\n" "-B,--buffer buffer size in frames\n" "-E,--period period size in frames\n" "-s,--seconds duration of test in seconds\n" "-b,--block block mode\n" "-p,--poll use poll (wait for event - reduces CPU usage)\n" "-e,--effect apply an effect (bandpass filter sweep)\n" ); printf("Recognized sample formats are:"); for (k = 0; k < SND_PCM_FORMAT_LAST; ++k) { const char *s = snd_pcm_format_name(k); if (s) printf(" %s", s); } printf("\n\n"); printf( "Tip #1 (usable latency with large periods, non-blocking mode, good CPU usage,\n" " superb xrun prevention):\n" " latency -m 8192 -M 8192 -t 1 -p\n" "Tip #2 (superb latency, non-blocking mode, but heavy CPU usage):\n" " latency -m 128 -M 128\n" ); } int main(int argc, char *argv[]) { struct option long_option[] = { {"help", 0, NULL, 'h'}, {"pdevice", 1, NULL, 'P'}, {"cdevice", 1, NULL, 'C'}, {"min", 1, NULL, 'm'}, {"max", 1, NULL, 'M'}, {"frames", 1, NULL, 'F'}, {"format", 1, NULL, 'f'}, {"channels", 1, NULL, 'c'}, {"rate", 1, NULL, 'r'}, {"buffer", 1, NULL, 'B'}, {"period", 1, NULL, 'E'}, {"seconds", 1, NULL, 's'}, {"block", 0, NULL, 'b'}, {"poll", 0, NULL, 'p'}, {"effect", 0, NULL, 'e'}, {NULL, 0, NULL, 0}, }; snd_pcm_t *phandle, *chandle; char *buffer; int err, latency, morehelp; int ok; snd_timestamp_t p_tstamp, c_tstamp; ssize_t r; size_t frames_in, frames_out, in_max; int effect = 0; morehelp = 0; while (1) { int c; if ((c = getopt_long(argc, argv, "hP:C:m:M:F:f:c:r:s:bpen", long_option, NULL)) < 0) break; switch (c) { case 'h': morehelp++; break; case 'P': pdevice = strdup(optarg); break; case 'C': cdevice = strdup(optarg); break; case 'm': err = atoi(optarg) / 2; latency_min = err >= 4 ? err : 4; if (latency_max < latency_min) latency_max = latency_min; break; case 'M': err = atoi(optarg) / 2; latency_max = latency_min > err ? latency_min : err; break; case 'f': format = snd_pcm_format_value(optarg); if (format == SND_PCM_FORMAT_UNKNOWN) { printf("Unknown format, setting to default S16_LE\n"); format = SND_PCM_FORMAT_S16_LE; } break; case 'c': err = atoi(optarg); channels = err >= 1 && err < 1024 ? err : 1; break; case 'r': err = atoi(optarg); rate = err >= 4000 && err < 200000 ? err : 44100; break; case 'B': err = atoi(optarg); buffer_size = err >= 32 && err < 200000 ? err : 0; break; case 'E': err = atoi(optarg); period_size = err >= 32 && err < 200000 ? err : 0; break; case 's': err = atoi(optarg); loop_sec = err >= 1 && err <= 100000 ? err : 30; break; case 'b': block = 1; break; case 'p': use_poll = 1; break; case 'e': effect = 1; break; case 'n': resample = 0; break; } } if (morehelp) { help(); return 0; } err = snd_output_stdio_attach(&output, stdout, 0); if (err < 0) { printf("Output failed: %s\n", snd_strerror(err)); return 0; } loop_limit = loop_sec * rate; latency = latency_min - 4; buffer = malloc((latency_max * snd_pcm_format_width(format) / 8) * 2); setscheduler(); printf("Playback device is %s\n", pdevice); printf("Capture device is %s\n", cdevice); printf("Parameters are %iHz, %s, %i channels, %s mode\n", rate, snd_pcm_format_name(format), channels, block ? "blocking" : "non-blocking"); printf("Poll mode: %s\n", use_poll ? "yes" : "no"); printf("Loop limit is %li frames, minimum latency = %i, maximum latency = %i\n", loop_limit, latency_min * 2, latency_max * 2); if ((err = snd_pcm_open(&phandle, pdevice, SND_PCM_STREAM_PLAYBACK, block ? 0 : SND_PCM_NONBLOCK)) < 0) { printf("Playback open error: %s\n", snd_strerror(err)); return 0; } if ((err = snd_pcm_open(&chandle, cdevice, SND_PCM_STREAM_CAPTURE, block ? 0 : SND_PCM_NONBLOCK)) < 0) { printf("Record open error: %s\n", snd_strerror(err)); return 0; } /* initialize the filter sweep variables */ if (effect) { fs = (float) rate; BW = FILTER_BANDWIDTH; lfo = 0; dlfo = 2.*M_PI*FILTERSWEEP_LFO_FREQ/fs; x[0] = (float*) malloc(channels*sizeof(float)); x[1] = (float*) malloc(channels*sizeof(float)); x[2] = (float*) malloc(channels*sizeof(float)); y[0] = (float*) malloc(channels*sizeof(float)); y[1] = (float*) malloc(channels*sizeof(float)); y[2] = (float*) malloc(channels*sizeof(float)); } while (1) { frames_in = frames_out = 0; if (setparams(phandle, chandle, &latency) < 0) break; showlatency(latency); if ((err = snd_pcm_link(chandle, phandle)) < 0) { printf("Streams link error: %s\n", snd_strerror(err)); exit(0); } if (snd_pcm_format_set_silence(format, buffer, latency*channels) < 0) { fprintf(stderr, "silence error\n"); break; } if (writebuf(phandle, buffer, latency, &frames_out) < 0) { fprintf(stderr, "write error\n"); break; } if (writebuf(phandle, buffer, latency, &frames_out) < 0) { fprintf(stderr, "write error\n"); break; } if ((err = snd_pcm_start(chandle)) < 0) { printf("Go error: %s\n", snd_strerror(err)); exit(0); } gettimestamp(phandle, &p_tstamp); gettimestamp(chandle, &c_tstamp); #if 0 printf("Playback:\n"); showstat(phandle, frames_out); printf("Capture:\n"); showstat(chandle, frames_in); #endif ok = 1; in_max = 0; while (ok && frames_in < loop_limit) { if (use_poll) { /* use poll to wait for next event */ snd_pcm_wait(chandle, 1000); } if ((r = readbuf(chandle, buffer, latency, &frames_in, &in_max)) < 0) ok = 0; else { if (effect) applyeffect(buffer,r); if (writebuf(phandle, buffer, r, &frames_out) < 0) ok = 0; } } if (ok) printf("Success\n"); else printf("Failure\n"); printf("Playback:\n"); showstat(phandle, frames_out); printf("Capture:\n"); showstat(chandle, frames_in); showinmax(in_max); if (p_tstamp.tv_sec == p_tstamp.tv_sec && p_tstamp.tv_usec == c_tstamp.tv_usec) printf("Hardware sync\n"); snd_pcm_drop(chandle); snd_pcm_nonblock(phandle, 0); snd_pcm_drain(phandle); snd_pcm_nonblock(phandle, !block ? 1 : 0); if (ok) { #if 1 printf("Playback time = %li.%i, Record time = %li.%i, diff = %li\n", p_tstamp.tv_sec, (int)p_tstamp.tv_usec, c_tstamp.tv_sec, (int)c_tstamp.tv_usec, timediff(p_tstamp, c_tstamp)); #endif break; } snd_pcm_unlink(chandle); snd_pcm_hw_free(phandle); snd_pcm_hw_free(chandle); } snd_pcm_close(phandle); snd_pcm_close(chandle); return 0; }
1.7.3
