gstreamer/ext/alsa/gstalsa.c

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/* Copyright (C) 2006 Tim-Philipp Müller <tim centricular net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the Free
* Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "gstalsa.h"
#include <gst/audio/multichannel.h>
static GstCaps *
gst_alsa_detect_rates (GstObject * obj, snd_pcm_hw_params_t * hw_params,
GstCaps * in_caps)
{
GstCaps *caps;
guint min, max;
gint err, dir, min_rate, max_rate, i;
GST_LOG_OBJECT (obj, "probing sample rates ...");
if ((err = snd_pcm_hw_params_get_rate_min (hw_params, &min, &dir)) < 0)
goto min_rate_err;
if ((err = snd_pcm_hw_params_get_rate_max (hw_params, &max, &dir)) < 0)
goto max_rate_err;
min_rate = min;
max_rate = max;
if (min_rate < 4000)
min_rate = 4000; /* random 'sensible minimum' */
if (max_rate <= 0)
max_rate = G_MAXINT; /* or maybe just use 192400 or so? */
else if (max_rate > 0 && max_rate < 4000)
max_rate = MAX (4000, min_rate);
GST_DEBUG_OBJECT (obj, "Min. rate = %u (%d)", min_rate, min);
GST_DEBUG_OBJECT (obj, "Max. rate = %u (%d)", max_rate, max);
caps = gst_caps_make_writable (in_caps);
for (i = 0; i < gst_caps_get_size (caps); ++i) {
GstStructure *s;
s = gst_caps_get_structure (caps, i);
if (min_rate == max_rate) {
gst_structure_set (s, "rate", G_TYPE_INT, min_rate, NULL);
} else {
gst_structure_set (s, "rate", GST_TYPE_INT_RANGE,
min_rate, max_rate, NULL);
}
}
return caps;
/* ERRORS */
min_rate_err:
{
GST_ERROR_OBJECT (obj, "failed to query minimum sample rate: %s",
snd_strerror (err));
gst_caps_unref (in_caps);
return NULL;
}
max_rate_err:
{
GST_ERROR_OBJECT (obj, "failed to query maximum sample rate: %s",
snd_strerror (err));
gst_caps_unref (in_caps);
return NULL;
}
}
static const struct
{
const int width;
const int depth;
const int sformat;
const int uformat;
} pcmformats[] = {
{
8, 8, SND_PCM_FORMAT_S8, SND_PCM_FORMAT_U8}, {
16, 16, SND_PCM_FORMAT_S16, SND_PCM_FORMAT_U16}, {
32, 24, SND_PCM_FORMAT_S24, SND_PCM_FORMAT_U24}, {
#if (G_BYTE_ORDER == G_LITTLE_ENDIAN) /* no endian-unspecific enum available */
24, 24, SND_PCM_FORMAT_S24_3LE, SND_PCM_FORMAT_U24_3LE}, {
#else
24, 24, SND_PCM_FORMAT_S24_3BE, SND_PCM_FORMAT_U24_3BE}, {
#endif
32, 32, SND_PCM_FORMAT_S32, SND_PCM_FORMAT_U32}
};
static GstCaps *
gst_alsa_detect_formats (GstObject * obj, snd_pcm_hw_params_t * hw_params,
GstCaps * in_caps)
{
snd_pcm_format_mask_t *mask;
GstStructure *s;
GstCaps *caps;
gint i;
snd_pcm_format_mask_alloca (&mask);
snd_pcm_hw_params_get_format_mask (hw_params, mask);
caps = gst_caps_new_empty ();
for (i = 0; i < gst_caps_get_size (in_caps); ++i) {
GstStructure *scopy;
gint w, width = 0, depth = 0;
s = gst_caps_get_structure (in_caps, i);
if (!gst_structure_has_name (s, "audio/x-raw-int")) {
GST_WARNING_OBJECT (obj, "skipping non-int format");
continue;
}
if (!gst_structure_get_int (s, "width", &width) ||
!gst_structure_get_int (s, "depth", &depth))
continue;
if (width == 0 || (width % 8) != 0)
continue; /* Only full byte widths are valid */
for (w = 0; w < G_N_ELEMENTS (pcmformats); w++)
if (pcmformats[w].width == width && pcmformats[w].depth == depth)
break;
if (w == G_N_ELEMENTS (pcmformats))
continue; /* Unknown format */
if (snd_pcm_format_mask_test (mask, pcmformats[w].sformat) &&
snd_pcm_format_mask_test (mask, pcmformats[w].uformat)) {
/* template contains { true, false } or just one, leave it as it is */
scopy = gst_structure_copy (s);
} else if (snd_pcm_format_mask_test (mask, pcmformats[w].sformat)) {
scopy = gst_structure_copy (s);
gst_structure_set (scopy, "signed", G_TYPE_BOOLEAN, TRUE, NULL);
} else if (snd_pcm_format_mask_test (mask, pcmformats[w].uformat)) {
scopy = gst_structure_copy (s);
gst_structure_set (scopy, "signed", G_TYPE_BOOLEAN, FALSE, NULL);
} else {
scopy = NULL;
}
if (scopy) {
if (width > 8) {
/* TODO: proper endianness detection, for now it's CPU endianness only */
gst_structure_set (scopy, "endianness", G_TYPE_INT, G_BYTE_ORDER, NULL);
}
gst_caps_append_structure (caps, scopy);
}
}
gst_caps_unref (in_caps);
return caps;
}
/* we don't have channel mappings for more than this many channels */
#define GST_ALSA_MAX_CHANNELS 8
static GstStructure *
get_channel_free_structure (const GstStructure * in_structure)
{
GstStructure *s = gst_structure_copy (in_structure);
gst_structure_remove_field (s, "channels");
return s;
}
static void
caps_add_channel_configuration (GstCaps * caps,
const GstStructure * in_structure, gint min_chans, gint max_chans)
{
GstAudioChannelPosition pos[8] = {
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER,
GST_AUDIO_CHANNEL_POSITION_LFE,
GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT,
GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT
};
GstStructure *s = NULL;
gint c;
if (min_chans == max_chans && max_chans <= 2) {
s = get_channel_free_structure (in_structure);
gst_structure_set (s, "channels", G_TYPE_INT, max_chans, NULL);
gst_caps_append_structure (caps, s);
return;
}
g_assert (min_chans >= 1);
/* mono and stereo don't need channel configurations */
if (min_chans == 2) {
s = get_channel_free_structure (in_structure);
gst_structure_set (s, "channels", G_TYPE_INT, 2, NULL);
gst_caps_append_structure (caps, s);
} else if (min_chans == 1 && max_chans >= 2) {
s = get_channel_free_structure (in_structure);
gst_structure_set (s, "channels", GST_TYPE_INT_RANGE, 1, 2, NULL);
gst_caps_append_structure (caps, s);
}
/* don't know whether to use 2.1 or 3.0 here - but I suspect
* alsa might work around that/fix it somehow. Can we tell alsa
* what our channel layout is like? */
if (max_chans >= 3 && min_chans <= 3) {
GstAudioChannelPosition pos_21[3] = {
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
GST_AUDIO_CHANNEL_POSITION_LFE
};
s = get_channel_free_structure (in_structure);
gst_structure_set (s, "channels", G_TYPE_INT, 3, NULL);
gst_audio_set_channel_positions (s, pos_21);
gst_caps_append_structure (caps, s);
}
/* everything else (4, 6, 8 channels) needs a channel layout */
for (c = MAX (4, min_chans); c <= 8; c += 2) {
if (max_chans >= c) {
s = get_channel_free_structure (in_structure);
gst_structure_set (s, "channels", G_TYPE_INT, c, NULL);
gst_audio_set_channel_positions (s, pos);
gst_caps_append_structure (caps, s);
}
}
for (c = MAX (9, min_chans); c <= max_chans; ++c) {
GstAudioChannelPosition *ch_layout;
guint i;
ch_layout = g_new (GstAudioChannelPosition, c);
for (i = 0; i < c; ++i) {
ch_layout[i] = GST_AUDIO_CHANNEL_POSITION_NONE;
}
s = get_channel_free_structure (in_structure);
gst_structure_set (s, "channels", G_TYPE_INT, c, NULL);
gst_audio_set_channel_positions (s, ch_layout);
gst_caps_append_structure (caps, s);
g_free (ch_layout);
}
}
static GstCaps *
gst_alsa_detect_channels (GstObject * obj, snd_pcm_hw_params_t * hw_params,
GstCaps * in_caps)
{
GstCaps *caps;
guint min, max;
gint min_chans, max_chans;
gint err, i;
GST_LOG_OBJECT (obj, "probing channels ...");
if ((err = snd_pcm_hw_params_get_channels_min (hw_params, &min)) < 0)
goto min_chan_error;
if ((err = snd_pcm_hw_params_get_channels_max (hw_params, &max)) < 0)
goto max_chan_error;
/* note: the above functions may return (guint) -1 */
min_chans = min;
max_chans = max;
if (min_chans < 0) {
min_chans = 1;
max_chans = GST_ALSA_MAX_CHANNELS;
} else if (max_chans < 0) {
max_chans = GST_ALSA_MAX_CHANNELS;
}
if (min_chans > max_chans) {
gint temp;
GST_WARNING_OBJECT (obj, "minimum channels > maximum channels (%d > %d), "
"please fix your soundcard drivers", min, max);
temp = min_chans;
min_chans = max_chans;
max_chans = temp;
}
/* pro cards seem to return large numbers for min_channels */
if (min_chans > GST_ALSA_MAX_CHANNELS) {
GST_DEBUG_OBJECT (obj, "min_chans = %u, looks like a pro card", min_chans);
if (max_chans < min_chans) {
max_chans = min_chans;
} else {
/* only support [max_chans; max_chans] for these cards for now
* to avoid inflating the source caps with loads of structures ... */
min_chans = max_chans;
}
} else {
min_chans = MAX (min_chans, 1);
max_chans = MIN (GST_ALSA_MAX_CHANNELS, max_chans);
}
GST_DEBUG_OBJECT (obj, "Min. channels = %d (%d)", min_chans, min);
GST_DEBUG_OBJECT (obj, "Max. channels = %d (%d)", max_chans, max);
caps = gst_caps_new_empty ();
for (i = 0; i < gst_caps_get_size (in_caps); ++i) {
GstStructure *s;
GType field_type;
gint c_min = min_chans;
gint c_max = max_chans;
s = gst_caps_get_structure (in_caps, i);
/* the template caps might limit the number of channels (like alsasrc),
* in which case we don't want to return a superset, so hack around this
* for the two common cases where the channels are either a fixed number
* or a min/max range). Example: alsasrc template has channels = [1,2] and
* the detection will claim to support 8 channels for device 'plughw:0' */
field_type = gst_structure_get_field_type (s, "channels");
if (field_type == G_TYPE_INT) {
gst_structure_get_int (s, "channels", &c_min);
gst_structure_get_int (s, "channels", &c_max);
} else if (field_type == GST_TYPE_INT_RANGE) {
const GValue *val;
val = gst_structure_get_value (s, "channels");
c_min = CLAMP (gst_value_get_int_range_min (val), min_chans, max_chans);
c_max = CLAMP (gst_value_get_int_range_max (val), min_chans, max_chans);
} else {
c_min = min_chans;
c_max = max_chans;
}
caps_add_channel_configuration (caps, s, c_min, c_max);
}
gst_caps_unref (in_caps);
return caps;
/* ERRORS */
min_chan_error:
{
GST_ERROR_OBJECT (obj, "failed to query minimum channel count: %s",
snd_strerror (err));
return NULL;
}
max_chan_error:
{
GST_ERROR_OBJECT (obj, "failed to query maximum channel count: %s",
snd_strerror (err));
return NULL;
}
}
/*
* gst_alsa_probe_supported_formats:
*
* Takes the template caps and returns the subset which is actually
* supported by this device.
*
*/
GstCaps *
gst_alsa_probe_supported_formats (GstObject * obj, snd_pcm_t * handle,
const GstCaps * template_caps)
{
snd_pcm_hw_params_t *hw_params;
GstCaps *caps;
gint err;
snd_pcm_hw_params_alloca (&hw_params);
if ((err = snd_pcm_hw_params_any (handle, hw_params)) < 0)
goto error;
caps = gst_caps_copy (template_caps);
if (!(caps = gst_alsa_detect_formats (obj, hw_params, caps)))
goto subroutine_error;
if (!(caps = gst_alsa_detect_rates (obj, hw_params, caps)))
goto subroutine_error;
if (!(caps = gst_alsa_detect_channels (obj, hw_params, caps)))
goto subroutine_error;
return caps;
/* ERRORS */
error:
{
GST_ERROR_OBJECT (obj, "failed to query formats: %s", snd_strerror (err));
return NULL;
}
subroutine_error:
{
GST_ERROR_OBJECT (obj, "failed to query formats");
return NULL;
}
}
static gchar *
gst_alsa_find_device_name_no_handle (GstObject * obj, const gchar * devcard,
gint device_num, snd_pcm_stream_t stream)
{
snd_ctl_card_info_t *info = NULL;
snd_ctl_t *ctl = NULL;
gchar *ret = NULL;
gint dev = -1;
GST_LOG_OBJECT (obj, "[%s] device=%d", devcard, device_num);
if (snd_ctl_open (&ctl, devcard, 0) < 0)
return NULL;
snd_ctl_card_info_malloc (&info);
if (snd_ctl_card_info (ctl, info) < 0)
goto done;
while (snd_ctl_pcm_next_device (ctl, &dev) == 0 && dev >= 0) {
if (dev == device_num) {
snd_pcm_info_t *pcminfo;
snd_pcm_info_malloc (&pcminfo);
snd_pcm_info_set_device (pcminfo, dev);
snd_pcm_info_set_subdevice (pcminfo, 0);
snd_pcm_info_set_stream (pcminfo, stream);
if (snd_ctl_pcm_info (ctl, pcminfo) < 0) {
snd_pcm_info_free (pcminfo);
break;
}
ret = g_strdup (snd_pcm_info_get_name (pcminfo));
snd_pcm_info_free (pcminfo);
GST_LOG_OBJECT (obj, "name from pcminfo: %s", GST_STR_NULL (ret));
}
}
if (ret == NULL) {
char *name = NULL;
gint card;
GST_LOG_OBJECT (obj, "no luck so far, trying backup");
card = snd_ctl_card_info_get_card (info);
snd_card_get_name (card, &name);
ret = g_strdup (name);
free (name);
}
done:
snd_ctl_card_info_free (info);
snd_ctl_close (ctl);
return ret;
}
gchar *
gst_alsa_find_device_name (GstObject * obj, const gchar * device,
snd_pcm_t * handle, snd_pcm_stream_t stream)
{
gchar *ret = NULL;
if (device != NULL) {
gchar *dev, *comma;
gint devnum;
GST_LOG_OBJECT (obj, "Trying to get device name from string '%s'", device);
/* only want name:card bit, but not devices and subdevices */
dev = g_strdup (device);
if ((comma = strchr (dev, ','))) {
*comma = '\0';
devnum = atoi (comma + 1);
ret = gst_alsa_find_device_name_no_handle (obj, dev, devnum, stream);
}
g_free (dev);
}
if (ret == NULL && handle != NULL) {
snd_pcm_info_t *info;
GST_LOG_OBJECT (obj, "Trying to get device name from open handle");
snd_pcm_info_malloc (&info);
snd_pcm_info (handle, info);
ret = g_strdup (snd_pcm_info_get_name (info));
snd_pcm_info_free (info);
}
GST_LOG_OBJECT (obj, "Device name for device '%s': %s",
GST_STR_NULL (device), GST_STR_NULL (ret));
return ret;
}