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/*
* Copyright (C) 2005-2007 Andre Noll <maan@systemlinux.org>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
/** \file alsa_write.c paraslash's alsa output plugin */
/*
* Based in parts on aplay.c from the alsa-utils-1.0.8 package,
* Copyright (c) by Jaroslav Kysela <perex@suse.cz>, which is
* based on the vplay program by Michael Beck.
*/
#include "para.h"
#include "fd.h"
#include "string.h"
#include "list.h"
#include "sched.h"
#include "write.h"
#include <alsa/asoundlib.h>
#include "alsa_write.cmdline.h"
#include "error.h"
/** always use 16 bit little endian */
#define FORMAT SND_PCM_FORMAT_S16_LE
/** data specific to the alsa writer */
struct private_alsa_write_data {
/** the alsa handle */
snd_pcm_t *handle;
/** determined and set by alsa_open() */
size_t bytes_per_frame;
/** don't write anything until this time */
struct timeval next_chunk;
/** the return value of snd_pcm_hw_params_get_buffer_time_max() */
unsigned buffer_time;
/**
* the samplerate given by command line option or the decoder
* of the writer node group
*/
unsigned samplerate;
/**
* the number of channels, also given by command line option or the
* decoder of the writer node group
*/
unsigned channels;
};
/*
* open and prepare the PCM handle for writing
*
* Install PCM software and hardware configuration. Exit on errors.
*/
static int alsa_open(struct writer_node *w)
{
snd_pcm_hw_params_t *hwparams;
snd_pcm_sw_params_t *swparams;
snd_pcm_uframes_t buffer_size, xfer_align, start_threshold,
stop_threshold;
int err;
snd_pcm_info_t *info;
snd_pcm_uframes_t period_size;
struct private_alsa_write_data *pad = para_calloc(sizeof(struct
private_alsa_write_data));
struct alsa_write_args_info *conf = w->conf;
struct writer_node_group *wng = w->wng;
if (!conf->samplerate_given && wng->samplerate)
pad->samplerate = *wng->samplerate;
else
pad->samplerate = conf->samplerate_arg;
if (!conf->channels_given && wng->channels)
pad->channels = *wng->channels;
else
pad->channels = conf->channels_arg;
PARA_INFO_LOG("%d channel(s), %dHz\n", pad->channels, pad->samplerate);
w->private_data = pad;
snd_pcm_info_alloca(&info);
err = snd_pcm_open(&pad->handle, conf->device_arg,
SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
if (err < 0)
return -E_PCM_OPEN;
if ((err = snd_pcm_info(pad->handle, info)) < 0)
return -E_SND_PCM_INFO;
snd_pcm_hw_params_alloca(&hwparams);
snd_pcm_sw_params_alloca(&swparams);
if (snd_pcm_hw_params_any(pad->handle, hwparams) < 0)
return -E_BROKEN_CONF;
if (snd_pcm_hw_params_set_access(pad->handle, hwparams,
SND_PCM_ACCESS_RW_INTERLEAVED) < 0)
return -E_ACCESS_TYPE;
if (snd_pcm_hw_params_set_format(pad->handle, hwparams, FORMAT) < 0)
return -E_SAMPLE_FORMAT;
if (snd_pcm_hw_params_set_channels(pad->handle, hwparams,
pad->channels) < 0)
return -E_CHANNEL_COUNT;
if (snd_pcm_hw_params_set_rate_near(pad->handle, hwparams,
&pad->samplerate, 0) < 0)
return -E_SET_RATE;
err = snd_pcm_hw_params_get_buffer_time_max(hwparams, &pad->buffer_time, 0);
if (err < 0 || !pad->buffer_time)
return -E_GET_BUFFER_TIME;
PARA_INFO_LOG("buffer time: %d\n", pad->buffer_time);
if (snd_pcm_hw_params_set_buffer_time_near(pad->handle, hwparams,
&pad->buffer_time, 0) < 0)
return -E_SET_BUFFER_TIME;
if (snd_pcm_hw_params(pad->handle, hwparams) < 0)
return -E_HW_PARAMS;
snd_pcm_hw_params_get_period_size(hwparams, &period_size, 0);
snd_pcm_hw_params_get_buffer_size(hwparams, &buffer_size);
PARA_INFO_LOG("buffer size: %lu, period_size: %lu\n", buffer_size,
period_size);
if (period_size == buffer_size)
return -E_BAD_PERIOD;
snd_pcm_sw_params_current(pad->handle, swparams);
err = snd_pcm_sw_params_get_xfer_align(swparams, &xfer_align);
if (err < 0 || !xfer_align)
return -E_GET_XFER;
snd_pcm_sw_params_set_avail_min(pad->handle, swparams, period_size);
/* round to closest transfer boundary */
start_threshold = (buffer_size / xfer_align) * xfer_align;
if (start_threshold < 1)
start_threshold = 1;
if (snd_pcm_sw_params_set_start_threshold(pad->handle, swparams,
start_threshold) < 0)
return -E_START_THRESHOLD;
stop_threshold = buffer_size;
if (snd_pcm_sw_params_set_stop_threshold(pad->handle, swparams,
stop_threshold) < 0)
return -E_STOP_THRESHOLD;
if (snd_pcm_sw_params_set_xfer_align(pad->handle, swparams,
xfer_align) < 0)
return -E_SET_XFER;
if (snd_pcm_sw_params(pad->handle, swparams) < 0)
return -E_SW_PARAMS;
pad->bytes_per_frame = snd_pcm_format_physical_width(FORMAT)
* pad->channels / 8;
if (snd_pcm_nonblock(pad->handle, 1))
PARA_ERROR_LOG("%s\n", "failed to set nonblock mode");
return period_size * pad->bytes_per_frame;
}
static int alsa_write_pre_select(struct sched *s, struct writer_node *wn)
{
struct private_alsa_write_data *pad = wn->private_data;
struct writer_node_group *wng = wn->wng;
struct timeval diff;
if (*wng->loaded < pad->bytes_per_frame)
return 1;
if (tv_diff(now, &pad->next_chunk, &diff) < 0) {
if (tv_diff(&s->timeout, &diff, NULL) > 0)
s->timeout = diff;
} else {
s->timeout.tv_sec = 0;
s->timeout.tv_usec = 1;
}
return 1;
// PARA_INFO_LOG("timeout: %lu\n", tv2ms(&s->timeout));
}
static int alsa_write_post_select(__a_unused struct sched *s,
struct writer_node *wn)
{
struct private_alsa_write_data *pad = wn->private_data;
struct writer_node_group *wng = wn->wng;
size_t frames = (*wng->loaded - wn->written) / pad->bytes_per_frame;
snd_pcm_sframes_t ret;
unsigned char *data = (unsigned char*)wng->buf + wn->written;
struct timeval tv;
// PARA_INFO_LOG("%zd frames\n", frames);
if (!frames) {
if (*wng->input_eof)
wn->written = *wng->loaded;
return 1;
}
if (tv_diff(now, &pad->next_chunk, NULL) < 0)
return 1;
ret = snd_pcm_writei(pad->handle, data, frames);
if (ret == -EPIPE) {
PARA_WARNING_LOG("%s", "EPIPE\n");
snd_pcm_prepare(pad->handle);
return 1;
}
if (ret < 0) {
PARA_WARNING_LOG("%s", "ALSA ERROR\n");
return -E_ALSA_WRITE;
}
ms2tv(pad->buffer_time / 4000, &tv);
// ms2tv(1, &tv);
tv_add(now, &tv, &pad->next_chunk);
wn->written += ret * pad->bytes_per_frame;
return 1;
}
static void alsa_close(struct writer_node *wn)
{
struct private_alsa_write_data *pad = wn->private_data;
PARA_INFO_LOG("closing writer node %p\n", wn);
snd_pcm_drain(pad->handle);
snd_pcm_close(pad->handle);
snd_config_update_free_global();
free(pad);
}
__malloc static void *alsa_parse_config(const char *options)
{
struct alsa_write_args_info *conf
= para_calloc(sizeof(struct alsa_write_args_info));
PARA_INFO_LOG("options: %s, %zd\n", options, strcspn(options, " \t"));
int ret = alsa_cmdline_parser_string(options, conf, "alsa_write");
if (ret)
goto err_out;
PARA_INFO_LOG("help given: %d\n", conf->help_given);
return conf;
err_out:
free(conf);
return NULL;
}
/**
* the init function of the alsa writer
*
* \param w pointer to the writer to initialize
*
* \sa struct writer
*/
void alsa_write_init(struct writer *w)
{
w->open = alsa_open;
w->close = alsa_close;
w->pre_select = alsa_write_pre_select;
w->post_select = alsa_write_post_select;
w->parse_config = alsa_parse_config;
w->shutdown = NULL; /* nothing to do */
}
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