Code copied from xawtv3
Signed-off-by: Bård Eirik Winther <bwint...@cisco.com>
---
utils/qv4l2/alsa_stream.c | 645 ++++++++++++++++++++++++++++++++++++++++++++++
utils/qv4l2/alsa_stream.h | 5 +
2 files changed, 650 insertions(+)
create mode 100644 utils/qv4l2/alsa_stream.c
create mode 100644 utils/qv4l2/alsa_stream.h
diff --git a/utils/qv4l2/alsa_stream.c b/utils/qv4l2/alsa_stream.c
new file mode 100644
index 0000000..3e33b5e
--- /dev/null
+++ b/utils/qv4l2/alsa_stream.c
@@ -0,0 +1,645 @@
+/*
+ * ALSA streaming support
+ *
+ * Originally written by:
+ * Copyright (c) by Devin Heitmueller <dheitmuel...@kernellabs.com>
+ * for usage at tvtime
+ * Derived from the alsa-driver test tool latency.c:
+ * Copyright (c) by Jaroslav Kysela <pe...@perex.cz>
+ *
+ * Copyright (c) 2011 - Mauro Carvalho Chehab <mche...@redhat.com>
+ * Ported to xawtv, with bug fixes and improvements
+ *
+ * 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 "config.h"
+
+#ifdef HAVE_ALSA_ASOUNDLIB_H
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sched.h>
+#include <errno.h>
+#include <getopt.h>
+#include <pthread.h>
+#include <alsa/asoundlib.h>
+#include <sys/time.h>
+#include <math.h>
+#include "alsa_stream.h"
+
+#define ARRAY_SIZE(a) (sizeof(a)/sizeof(*(a)))
+
+/* Private vars to control alsa thread status */
+static int stop_alsa = 0;
+
+/* Error handlers */
+snd_output_t *output = NULL;
+FILE *error_fp;
+int verbose = 0;
+
+struct final_params {
+ int bufsize;
+ int rate;
+ int latency;
+ int channels;
+};
+
+static int setparams_stream(snd_pcm_t *handle,
+ snd_pcm_hw_params_t *params,
+ snd_pcm_format_t format,
+ int *channels,
+ const char *id)
+{
+ int err;
+
+ err = snd_pcm_hw_params_any(handle, params);
+ if (err < 0) {
+ fprintf(error_fp,
+ "alsa: Broken configuration for %s PCM: no configurations
available: %s\n",
+ snd_strerror(err), id);
+ return err;
+ }
+
+ err = snd_pcm_hw_params_set_access(handle, params,
+ SND_PCM_ACCESS_RW_INTERLEAVED);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: 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) {
+ fprintf(error_fp, "alsa: Sample format not available for %s: %s\n", id,
+ snd_strerror(err));
+ return err;
+ }
+
+retry:
+ err = snd_pcm_hw_params_set_channels(handle, params, *channels);
+ if (err < 0) {
+ if (strcmp(id, "capture") == 0 && *channels == 2) {
+ *channels = 1;
+ goto retry; /* Retry with mono capture */
+ }
+ fprintf(error_fp, "alsa: Channels count (%i) not available for %s:
%s\n",
+ *channels, id, snd_strerror(err));
+ return err;
+ }
+
+ return 0;
+}
+
+static void getparams_periods(snd_pcm_t *handle,
+ snd_pcm_hw_params_t *params,
+ unsigned int *usecs,
+ unsigned int *count,
+ const char *id)
+{
+ unsigned min = 0, max = 0;
+
+ snd_pcm_hw_params_get_periods_min(params, &min, 0);
+ snd_pcm_hw_params_get_periods_max(params, &max, 0);
+ if (min && max) {
+ if (verbose)
+ fprintf(error_fp, "alsa: %s periods range between %u and %u. Want:
%u\n",
+ id, min, max, *count);
+ if (*count < min)
+ *count = min;
+ if (*count > max)
+ *count = max;
+ }
+
+ min = max = 0;
+ snd_pcm_hw_params_get_period_time_min(params, &min, 0);
+ snd_pcm_hw_params_get_period_time_max(params, &max, 0);
+ if (min && max) {
+ if (verbose)
+ fprintf(error_fp, "alsa: %s period time range between %u and %u.
Want: %u\n",
+ id, min, max, *usecs);
+ if (*usecs < min)
+ *usecs = min;
+ if (*usecs > max)
+ *usecs = max;
+ }
+}
+
+static int setparams_periods(snd_pcm_t *handle,
+ snd_pcm_hw_params_t *params,
+ unsigned int *usecs,
+ unsigned int *count,
+ const char *id)
+{
+ int err;
+
+ err = snd_pcm_hw_params_set_period_time_near(handle, params, usecs, 0);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: Unable to set period time %u for %s: %s\n",
+ *usecs, id, snd_strerror(err));
+ return err;
+ }
+
+ err = snd_pcm_hw_params_set_periods_near(handle, params, count, 0);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: Unable to set %u periods for %s: %s\n",
+ *count, id, snd_strerror(err));
+ return err;
+ }
+
+ if (verbose)
+ fprintf(error_fp, "alsa: %s period set to %u periods of %u time\n",
+ id, *count, *usecs);
+
+ return 0;
+}
+
+static int setparams_set(snd_pcm_t *handle,
+ snd_pcm_hw_params_t *params,
+ snd_pcm_sw_params_t *swparams,
+ snd_pcm_uframes_t start_treshold,
+ const char *id)
+{
+ int err;
+
+ err = snd_pcm_hw_params(handle, params);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: 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) {
+ fprintf(error_fp, "alsa: 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,
+ start_treshold);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: Unable to set start threshold mode for %s:
%s\n",
+ id, snd_strerror(err));
+ return err;
+ }
+
+ err = snd_pcm_sw_params_set_avail_min(handle, swparams, 4);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: 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) {
+ fprintf(error_fp, "alsa: Unable to set sw params for %s: %s\n",
+ id, snd_strerror(err));
+ return err;
+ }
+ return 0;
+}
+
+static int alsa_try_rate(snd_pcm_t *phandle, snd_pcm_t *chandle,
+ snd_pcm_hw_params_t *p_hwparams,
+ snd_pcm_hw_params_t *c_hwparams,
+ int allow_resample, unsigned *ratep, unsigned *ratec)
+{
+ int err;
+
+ err = snd_pcm_hw_params_set_rate_near(chandle, c_hwparams, ratec, 0);
+ if (err)
+ return err;
+
+ *ratep = *ratec;
+ err = snd_pcm_hw_params_set_rate_near(phandle, p_hwparams, ratep, 0);
+ if (err)
+ return err;
+
+ if (*ratep == *ratec)
+ return 0;
+
+ if (verbose)
+ fprintf(error_fp,
+ "alsa_try_rate: capture wanted %u, playback wanted %u%s\n",
+ *ratec, *ratep, allow_resample ? " with resample enabled": "");
+
+ return 1; /* No error, but also no match */
+}
+
+static int setparams(snd_pcm_t *phandle, snd_pcm_t *chandle,
+ snd_pcm_format_t format,
+ int latency, int allow_resample,
+ struct final_params *negotiated)
+{
+ int i;
+ unsigned ratep, ratec = 0;
+ unsigned ratemin = 32000, ratemax = 96000, val;
+ int err, channels = 2;
+ snd_pcm_hw_params_t *p_hwparams, *c_hwparams;
+ snd_pcm_sw_params_t *p_swparams, *c_swparams;
+ snd_pcm_uframes_t c_size, p_psize, c_psize;
+ /* Our latency is 2 periods (in usecs) */
+ unsigned int c_periods = 2, p_periods;
+ unsigned int c_periodtime, p_periodtime;
+ const unsigned int prefered_rates[] = { 44100, 48000, 32000 };
+
+ snd_pcm_hw_params_alloca(&p_hwparams);
+ snd_pcm_hw_params_alloca(&c_hwparams);
+ snd_pcm_sw_params_alloca(&p_swparams);
+ snd_pcm_sw_params_alloca(&c_swparams);
+
+ if (setparams_stream(chandle, c_hwparams, format, &channels, "capture"))
+ return 1;
+
+ if (setparams_stream(phandle, p_hwparams, format, &channels, "playback"))
+ return 1;
+
+ if (allow_resample) {
+ err = snd_pcm_hw_params_set_rate_resample(chandle, c_hwparams, 1);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: Resample setup failed: %s\n",
snd_strerror(err));
+ return 1;
+ } else if (verbose)
+ fprintf(error_fp, "alsa: Resample enabled.\n");
+ }
+
+ err = snd_pcm_hw_params_get_rate_min(c_hwparams, &ratemin, 0);
+ if (err >= 0 && verbose)
+ fprintf(error_fp, "alsa: Capture min rate is %d\n", ratemin);
+ err = snd_pcm_hw_params_get_rate_max(c_hwparams, &ratemax, 0);
+ if (err >= 0 && verbose)
+ fprintf(error_fp, "alsa: Capture max rate is %u\n", ratemax);
+
+ err = snd_pcm_hw_params_get_rate_min(p_hwparams, &val, 0);
+ if (err >= 0) {
+ if (verbose)
+ fprintf(error_fp, "alsa: Playback min rate is %u\n", val);
+ if (val > ratemin)
+ ratemin = val;
+ }
+ err = snd_pcm_hw_params_get_rate_max(p_hwparams, &val, 0);
+ if (err >= 0) {
+ if (verbose)
+ fprintf(error_fp, "alsa: Playback max rate is %u\n", val);
+ if (val < ratemax)
+ ratemax = val;
+ }
+
+ if (verbose)
+ fprintf(error_fp,
+ "alsa: Will search a common rate between %u and %u\n",
+ ratemin, ratemax);
+
+ /* First try a set of common rates */
+ err = -1;
+ for (i = 0; i < ARRAY_SIZE(prefered_rates); i++) {
+ if (prefered_rates[i] < ratemin || prefered_rates[i] > ratemax)
+ continue;
+ ratep = ratec = prefered_rates[i];
+ err = alsa_try_rate(phandle, chandle, p_hwparams, c_hwparams,
+ allow_resample, &ratep, &ratec);
+ if (err == 0)
+ break;
+ }
+
+ if (err != 0) {
+ if (ratemin >= 44100) {
+ for (i = ratemin; i <= ratemax; i += 100) {
+ ratep = ratec = i;
+ err = alsa_try_rate(phandle, chandle, p_hwparams, c_hwparams,
+ allow_resample, &ratep, &ratec);
+ if (err == 0)
+ break;
+ }
+ } else {
+ for (i = ratemax; i >= ratemin; i -= 100) {
+ ratep = ratec = i;
+ err = alsa_try_rate(phandle, chandle, p_hwparams, c_hwparams,
+ allow_resample, &ratep, &ratec);
+ if (err == 0)
+ break;
+ }
+ }
+ }
+
+ if (err < 0) {
+ fprintf(error_fp, "alsa: Failed to set a supported rate: %s\n",
+ snd_strerror(err));
+ return 1;
+ }
+ if (ratep != ratec) {
+ if (verbose || allow_resample)
+ fprintf(error_fp,
+ "alsa: Couldn't find a rate that it is supported by both
playback and capture\n");
+ return 2;
+ }
+ if (verbose)
+ fprintf(error_fp, "alsa: Using Rate %d\n", ratec);
+
+ /* Negotiate period parameters */
+
+ c_periodtime = latency * 1000 / c_periods;
+ getparams_periods(chandle, c_hwparams, &c_periodtime, &c_periods,
"capture");
+ p_periods = c_periods * 2;
+ p_periodtime = c_periodtime;
+ getparams_periods(phandle, p_hwparams, &p_periodtime, &p_periods,
"playback");
+ c_periods = p_periods / 2;
+
+ /*
+ * Some playback devices support a very limited periodtime range. If the
user needs to
+ * use a higher latency to avoid overrun/underrun, use an alternate
algorithm of incresing
+ * the number of periods, to archive the needed latency
+ */
+ if (p_periodtime < c_periodtime) {
+ c_periodtime = p_periodtime;
+ c_periods = round (latency * 1000.0 / c_periodtime + 0.5);
+ getparams_periods(chandle, c_hwparams, &c_periodtime, &c_periods,
"capture");
+ p_periods = c_periods * 2;
+ p_periodtime = c_periodtime;
+ getparams_periods(phandle, p_hwparams, &p_periodtime, &p_periods,
"playback");
+ c_periods = p_periods / 2;
+ }
+
+ if (setparams_periods(chandle, c_hwparams, &c_periodtime, &c_periods,
"capture"))
+ return 1;
+
+ /* Note we use twice as much periods for the playback buffer, since we
+ will get a period size near the requested time and we don't want it to
+ end up smaller then the capture buffer as then we could end up blocking
+ on writing to it. Note we will configure the playback dev to start
+ playing as soon as it has 2 capture periods worth of data, so this
+ won't influence latency */
+ if (setparams_periods(phandle, p_hwparams, &p_periodtime, &p_periods,
"playback"))
+ return 1;
+
+ snd_pcm_hw_params_get_period_size(p_hwparams, &p_psize, NULL);
+ snd_pcm_hw_params_get_period_size(c_hwparams, &c_psize, NULL);
+ snd_pcm_hw_params_get_buffer_size(c_hwparams, &c_size);
+
+ latency = c_periods * c_psize;
+ if (setparams_set(phandle, p_hwparams, p_swparams, latency, "playback"))
+ return 1;
+
+ if (setparams_set(chandle, c_hwparams, c_swparams, c_psize, "capture"))
+ return 1;
+
+ if ((err = snd_pcm_prepare(phandle)) < 0) {
+ fprintf(error_fp, "alsa: Prepare error: %s\n", snd_strerror(err));
+ return 1;
+ }
+
+ if (verbose) {
+ fprintf(error_fp, "alsa: Negociated configuration:\n");
+ snd_pcm_dump_setup(phandle, output);
+ snd_pcm_dump_setup(chandle, output);
+ fprintf(error_fp, "alsa: Parameters are %iHz, %s, %i channels\n",
+ ratep, snd_pcm_format_name(format), channels);
+ fprintf(error_fp, "alsa: Set bitrate to %u%s, buffer size is %u\n",
ratec,
+ allow_resample ? " with resample enabled at playback": "",
+ (unsigned int)c_size);
+ }
+
+ negotiated->bufsize = c_size;
+ negotiated->rate = ratep;
+ negotiated->channels = channels;
+ negotiated->latency = latency;
+ return 0;
+}
+
+/* Read up to len frames */
+static snd_pcm_sframes_t readbuf(snd_pcm_t *handle, char *buf, long len)
+{
+ snd_pcm_sframes_t r;
+
+ r = snd_pcm_readi(handle, buf, len);
+ if (r < 0 && r != -EAGAIN) {
+ r = snd_pcm_recover(handle, r, 0);
+ if (r < 0)
+ fprintf(error_fp, "alsa: overrun recover error: %s\n",
snd_strerror(r));
+ }
+ return r;
+}
+
+/* Write len frames (note not up to len, but all of len!) */
+static snd_pcm_sframes_t writebuf(snd_pcm_t *handle, char *buf, long len)
+{
+ snd_pcm_sframes_t r;
+
+ while (1) {
+ r = snd_pcm_writei(handle, buf, len);
+ if (r == len)
+ return 0;
+ if (r < 0) {
+ r = snd_pcm_recover(handle, r, 0);
+ if (r < 0) {
+ fprintf(error_fp, "alsa: underrun recover error: %s\n",
+ snd_strerror(r));
+ return r;
+ }
+ }
+ buf += r * 4;
+ len -= r;
+ snd_pcm_wait(handle, 100);
+ }
+}
+
+static int alsa_stream(const char *pdevice, const char *cdevice, int latency)
+{
+ snd_pcm_t *phandle, *chandle;
+ char *buffer;
+ int err;
+ ssize_t r;
+ struct final_params negotiated;
+ snd_pcm_format_t format = SND_PCM_FORMAT_S16_LE;
+ char pdevice_new[32];
+
+ err = snd_output_stdio_attach(&output, error_fp, 0);
+ if (err < 0) {
+ fprintf(error_fp, "alsa: Output failed: %s\n", snd_strerror(err));
+ return 0;
+ }
+
+ /* Open the devices */
+ if ((err = snd_pcm_open(&phandle, pdevice, SND_PCM_STREAM_PLAYBACK,
+ 0)) < 0) {
+ fprintf(error_fp, "alsa: Cannot open playback device %s: %s\n",
+ pdevice, snd_strerror(err));
+ return 0;
+ }
+ if ((err = snd_pcm_open(&chandle, cdevice, SND_PCM_STREAM_CAPTURE,
+ SND_PCM_NONBLOCK)) < 0) {
+ fprintf(error_fp, "alsa: Cannot open capture device %s: %s\n",
+ cdevice, snd_strerror(err));
+ snd_pcm_close(phandle);
+ return 0;
+ }
+
+ err = setparams(phandle, chandle, format, latency, 0, &negotiated);
+
+ /* Try to use plughw instead, as it allows emulating speed */
+ if (err == 2 && strncmp(pdevice, "hw", 2) == 0) {
+
+ snd_pcm_close(phandle);
+
+ sprintf(pdevice_new, "plug%s", pdevice);
+ pdevice = pdevice_new;
+ if (verbose)
+ fprintf(error_fp, "alsa: Trying %s for playback\n", pdevice);
+ if ((err = snd_pcm_open(&phandle, pdevice, SND_PCM_STREAM_PLAYBACK,
+ 0)) < 0) {
+ fprintf(error_fp, "alsa: Cannot open playback device %s: %s\n",
+ pdevice, snd_strerror(err));
+ snd_pcm_close(chandle);
+ return 0;
+ }
+
+ err = setparams(phandle, chandle, format, latency, 1, &negotiated);
+ }
+
+ if (err != 0) {
+ fprintf(error_fp, "alsa: setparams failed\n");
+ snd_pcm_close(phandle);
+ snd_pcm_close(chandle);
+ return 1;
+ }
+
+ buffer = malloc((negotiated.bufsize * snd_pcm_format_width(format) / 8)
+ * negotiated.channels);
+ if (buffer == NULL) {
+ fprintf(error_fp, "alsa: Failed allocating buffer for audio\n");
+ snd_pcm_close(phandle);
+ snd_pcm_close(chandle);
+ return 0;
+ }
+
+ if (verbose)
+ fprintf(error_fp,
+ "alsa: stream started from %s to %s (%i Hz, buffer delay = %.2f
ms)\n",
+ cdevice, pdevice, negotiated.rate,
+ negotiated.latency * 1000.0 / negotiated.rate);
+
+ while (!stop_alsa) {
+ /* We start with a read and not a wait to auto(re)start the capture */
+ r = readbuf(chandle, buffer, negotiated.bufsize);
+ if (r == 0) /* Succesfully recovered from an overrun? */
+ continue; /* Force restart of capture stream */
+ if (r > 0)
+ writebuf(phandle, buffer, r);
+ /* use poll to wait for next event */
+ while (!stop_alsa && !snd_pcm_wait(chandle, 50))
+ ;
+ }
+
+ snd_pcm_drop(chandle);
+ snd_pcm_drop(phandle);
+
+ snd_pcm_unlink(chandle);
+ snd_pcm_hw_free(phandle);
+ snd_pcm_hw_free(chandle);
+
+ snd_pcm_close(phandle);
+ snd_pcm_close(chandle);
+
+ return 0;
+}
+
+struct input_params {
+ char *pdevice;
+ char *cdevice;
+ int latency;
+};
+
+static void *alsa_thread_entry(void *whatever)
+{
+ struct input_params *inputs = (struct input_params *) whatever;
+
+ if (verbose)
+ fprintf(error_fp, "alsa: starting copying alsa stream from %s to %s\n",
+ inputs->cdevice, inputs->pdevice);
+ alsa_stream(inputs->pdevice, inputs->cdevice, inputs->latency);
+ if (verbose)
+ fprintf(error_fp, "alsa: stream stopped\n");
+
+ free(inputs->pdevice);
+ free(inputs->cdevice);
+ free(inputs);
+
+ return NULL;
+}
+
+/*************************************************************************
+ Public functions
+ *************************************************************************/
+
+static int alsa_is_running = 0;
+static pthread_t alsa_thread;
+
+int alsa_thread_startup(const char *pdevice, const char *cdevice, int latency,
+ FILE *__error_fp, int __verbose)
+{
+ int ret;
+ struct input_params *inputs;
+
+ if ((strcasecmp(pdevice, "disabled") == 0) ||
+ (strcasecmp(cdevice, "disabled") == 0))
+ return 0;
+
+ if (__error_fp)
+ error_fp = __error_fp;
+ else
+ error_fp = stderr;
+
+ verbose = __verbose;
+
+ if (alsa_is_running) {
+ fprintf(error_fp, "alsa: Already running\n");
+ return EBUSY;
+ }
+
+ inputs = malloc(sizeof(struct input_params));
+ if (inputs == NULL) {
+ fprintf(error_fp, "alsa: failed allocating memory for inputs\n");
+ return ENOMEM;
+ }
+
+ inputs->pdevice = strdup(pdevice);
+ inputs->cdevice = strdup(cdevice);
+ inputs->latency = latency;
+
+ stop_alsa = 0;
+ ret = pthread_create(&alsa_thread, NULL,
+ &alsa_thread_entry, (void *) inputs);
+ if (ret == 0)
+ alsa_is_running = 1;
+
+ return ret;
+}
+
+void alsa_thread_stop(void)
+{
+ if (!alsa_is_running)
+ return;
+
+ stop_alsa = 1;
+ pthread_join(alsa_thread, NULL);
+ alsa_is_running = 0;
+}
+
+int alsa_thread_is_running(void)
+{
+ return alsa_is_running;
+}
+
+#endif
diff --git a/utils/qv4l2/alsa_stream.h b/utils/qv4l2/alsa_stream.h
new file mode 100644
index 0000000..c68fd6d
--- /dev/null
+++ b/utils/qv4l2/alsa_stream.h
@@ -0,0 +1,5 @@
+int alsa_thread_startup(const char *pdevice, const char *cdevice, int latency,
+ FILE *__error_fp,
+ int __verbose);
+void alsa_thread_stop(void);
+int alsa_thread_is_running(void);
--
1.8.3.2
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