gstreamer/ext/alsa/gstalsa.c
Tim-Philipp Müller 9d3a69fc58 ext/alsa/: Refactor and improve caps probing code: probe signedness when we probe the supported formats/widths; set e...
Original commit message from CVS:
* ext/alsa/Makefile.am:
* ext/alsa/gstalsa.c: (gst_alsa_detect_rates),
(gst_alsa_detect_formats), (get_channel_free_structure),
(caps_add_channel_configuration), (gst_alsa_detect_channels),
(gst_alsa_probe_supported_formats):
* ext/alsa/gstalsa.h:
* ext/alsa/gstalsasink.c: (gst_alsasink_getcaps):
Refactor and improve caps probing code: probe signedness
when we probe the supported formats/widths; set endianness
to the one we actually probed for (ie. cpu endianness).
* ext/alsa/gstalsasrc.c: (gst_alsasrc_init), (gst_alsasrc_getcaps),
(gst_alsasrc_close):
* ext/alsa/gstalsasrc.h:
Implement caps probing for alsasrc.
2006-05-16 15:52:17 +00:00

362 lines
10 KiB
C

/* 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;
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 sformat;
const int uformat;
} pcmformats[4] = {
{
SND_PCM_FORMAT_S8, SND_PCM_FORMAT_U8}, {
SND_PCM_FORMAT_S16, SND_PCM_FORMAT_U16}, {
SND_PCM_FORMAT_UNKNOWN, SND_PCM_FORMAT_UNKNOWN}, {
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;
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;
}
gst_structure_get_int (s, "width", &width);
g_assert (width != 0 && (width % 8) == 0);
w = (width / 8) - 1;
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) {
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) {
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 = 4; 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);
}
}
}
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;
}
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;
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;
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;
}
}