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Surround sound support.

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Original commit message from CVS:
* ext/a52dec/gsta52dec.c: (gst_a52dec_channels), (gst_a52dec_push),
(gst_a52dec_reneg), (gst_a52dec_loop), (plugin_init):
* ext/alsa/gstalsa.c: (gst_alsa_get_caps):
* ext/alsa/gstalsaplugin.c: (plugin_init):
* ext/dts/gstdtsdec.c: (gst_dtsdec_channels),
(gst_dtsdec_renegotiate), (gst_dtsdec_loop), (plugin_init):
* ext/faad/gstfaad.c: (gst_faad_init), (gst_faad_chanpos_from_gst),
(gst_faad_chanpos_to_gst), (gst_faad_sinkconnect),
(gst_faad_srcgetcaps), (gst_faad_srcconnect), (gst_faad_chain),
(gst_faad_change_state), (plugin_init):
* ext/faad/gstfaad.h:
* ext/vorbis/vorbis.c: (plugin_init):
* ext/vorbis/vorbisdec.c: (vorbis_dec_chain):
* gst-libs/gst/audio/Makefile.am:
* gst-libs/gst/audio/audio.c: (plugin_init):
* gst-libs/gst/audio/multichannel.c:
(gst_audio_check_channel_positions),
(gst_audio_get_channel_positions),
(gst_audio_set_channel_positions),
(gst_audio_set_structure_channel_positions_list),
(add_list_to_struct), (gst_audio_set_caps_channel_positions_list),
(gst_audio_fixate_channel_positions):
* gst-libs/gst/audio/multichannel.h:
* gst-libs/gst/audio/testchannels.c: (main):
* gst/audioconvert/gstaudioconvert.c:
(gst_audio_convert_class_init), (gst_audio_convert_init),
(gst_audio_convert_dispose), (gst_audio_convert_getcaps),
(gst_audio_convert_parse_caps), (gst_audio_convert_link),
(gst_audio_convert_fixate), (gst_audio_convert_channels):
* gst/audioconvert/plugin.c: (plugin_init):
Surround sound support.
This commit is contained in:
Ronald S. Bultje 2004-11-25 20:36:29 +00:00
parent 69aa90e80b
commit f5595c1678
7 changed files with 934 additions and 149 deletions
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34
ChangeLog
View file

@ -1,3 +1,37 @@
2004-11-25 Ronald S. Bultje <rbultje@ronald.bitfreak.net>
* ext/a52dec/gsta52dec.c: (gst_a52dec_channels), (gst_a52dec_push),
(gst_a52dec_reneg), (gst_a52dec_loop), (plugin_init):
* ext/alsa/gstalsa.c: (gst_alsa_get_caps):
* ext/alsa/gstalsaplugin.c: (plugin_init):
* ext/dts/gstdtsdec.c: (gst_dtsdec_channels),
(gst_dtsdec_renegotiate), (gst_dtsdec_loop), (plugin_init):
* ext/faad/gstfaad.c: (gst_faad_init), (gst_faad_chanpos_from_gst),
(gst_faad_chanpos_to_gst), (gst_faad_sinkconnect),
(gst_faad_srcgetcaps), (gst_faad_srcconnect), (gst_faad_chain),
(gst_faad_change_state), (plugin_init):
* ext/faad/gstfaad.h:
* ext/vorbis/vorbis.c: (plugin_init):
* ext/vorbis/vorbisdec.c: (vorbis_dec_chain):
* gst-libs/gst/audio/Makefile.am:
* gst-libs/gst/audio/audio.c: (plugin_init):
* gst-libs/gst/audio/multichannel.c:
(gst_audio_check_channel_positions),
(gst_audio_get_channel_positions),
(gst_audio_set_channel_positions),
(gst_audio_set_structure_channel_positions_list),
(add_list_to_struct), (gst_audio_set_caps_channel_positions_list),
(gst_audio_fixate_channel_positions):
* gst-libs/gst/audio/multichannel.h:
* gst-libs/gst/audio/testchannels.c: (main):
* gst/audioconvert/gstaudioconvert.c:
(gst_audio_convert_class_init), (gst_audio_convert_init),
(gst_audio_convert_dispose), (gst_audio_convert_getcaps),
(gst_audio_convert_parse_caps), (gst_audio_convert_link),
(gst_audio_convert_fixate), (gst_audio_convert_channels):
* gst/audioconvert/plugin.c: (plugin_init):
Surround sound support.
2004-11-25 Ronald S. Bultje <rbultje@ronald.bitfreak.net>
* ext/ogg/gstoggdemux.c: (gst_ogg_demux_push):

241
ext/a52dec/gsta52dec.c
View file

@ -27,6 +27,8 @@
#include "_stdint.h"
#include <gst/gst.h>
#include <gst/audio/multichannel.h>
#include <a52dec/a52.h>
#include <a52dec/mm_accel.h>
#include "gsta52dec.h"
@ -39,6 +41,12 @@ static GstElementDetails gst_a52dec_details = {
"David I. Lehn <dlehn@users.sourceforge.net>",
};
#ifdef LIBA52_DOUBLE
#define SAMPLE_WIDTH 64
#else
#define SAMPLE_WIDTH 32
#endif
GST_DEBUG_CATEGORY_STATIC (a52dec_debug);
#define GST_CAT_DEFAULT (a52dec_debug)
@ -68,12 +76,10 @@ static GstStaticPadTemplate sink_factory = GST_STATIC_PAD_TEMPLATE ("sink",
static GstStaticPadTemplate src_factory = GST_STATIC_PAD_TEMPLATE ("src",
GST_PAD_SRC,
GST_PAD_ALWAYS,
GST_STATIC_CAPS ("audio/x-raw-int, "
GST_STATIC_CAPS ("audio/x-raw-float, "
"endianness = (int) BYTE_ORDER, "
"signed = (boolean) true, "
"width = (int) 16, "
"depth = (int) 16, "
"rate = (int) [ 4000, 48000 ], " "channels = (int) [ 1, 6 ]")
"width = (int) " G_STRINGIFY (SAMPLE_WIDTH) ", "
"rate = (int) [ 4000, 96000 ], " "channels = (int) [ 1, 6 ]")
);
static void gst_a52dec_base_init (gpointer g_class);
@ -170,176 +176,108 @@ gst_a52dec_init (GstA52Dec * a52dec)
a52dec->dynamic_range_compression = FALSE;
}
/* BEGIN modified a52dec conversion code */
static inline int16_t
convert (int32_t i)
{
if (i > 0x43c07fff)
return 32767;
else if (i < 0x43bf8000)
return -32768;
else
return i - 0x43c00000;
}
static inline void
float_to_int (float *_f, int16_t * s16, int flags)
{
int i;
int32_t *f = (int32_t *) _f;
switch (flags) {
case A52_MONO:
for (i = 0; i < 256; i++) {
s16[5 * i] = s16[5 * i + 1] = s16[5 * i + 2] = s16[5 * i + 3] = 0;
s16[5 * i + 4] = convert (f[i]);
}
break;
case A52_CHANNEL:
case A52_STEREO:
case A52_DOLBY:
for (i = 0; i < 256; i++) {
s16[2 * i] = convert (f[i]);
s16[2 * i + 1] = convert (f[i + 256]);
}
break;
case A52_3F:
for (i = 0; i < 256; i++) {
s16[5 * i] = convert (f[i]);
s16[5 * i + 1] = convert (f[i + 512]);
s16[5 * i + 2] = s16[5 * i + 3] = 0;
s16[5 * i + 4] = convert (f[i + 256]);
}
break;
case A52_2F2R:
for (i = 0; i < 256; i++) {
s16[4 * i] = convert (f[i]);
s16[4 * i + 1] = convert (f[i + 256]);
s16[4 * i + 2] = convert (f[i + 512]);
s16[4 * i + 3] = convert (f[i + 768]);
}
break;
case A52_3F2R:
for (i = 0; i < 256; i++) {
s16[5 * i] = convert (f[i]);
s16[5 * i + 1] = convert (f[i + 512]);
s16[5 * i + 2] = convert (f[i + 768]);
s16[5 * i + 3] = convert (f[i + 1024]);
s16[5 * i + 4] = convert (f[i + 256]);
}
break;
case A52_MONO | A52_LFE:
for (i = 0; i < 256; i++) {
s16[6 * i] = s16[6 * i + 1] = s16[6 * i + 2] = s16[6 * i + 3] = 0;
s16[6 * i + 4] = convert (f[i + 256]);
s16[6 * i + 5] = convert (f[i]);
}
break;
case A52_CHANNEL | A52_LFE:
case A52_STEREO | A52_LFE:
case A52_DOLBY | A52_LFE:
for (i = 0; i < 256; i++) {
s16[6 * i] = convert (f[i + 256]);
s16[6 * i + 1] = convert (f[i + 512]);
s16[6 * i + 2] = s16[6 * i + 3] = s16[6 * i + 4] = 0;
s16[6 * i + 5] = convert (f[i]);
}
break;
case A52_3F | A52_LFE:
for (i = 0; i < 256; i++) {
s16[6 * i] = convert (f[i + 256]);
s16[6 * i + 1] = convert (f[i + 768]);
s16[6 * i + 2] = s16[6 * i + 3] = 0;
s16[6 * i + 4] = convert (f[i + 512]);
s16[6 * i + 5] = convert (f[i]);
}
break;
case A52_2F2R | A52_LFE:
for (i = 0; i < 256; i++) {
s16[6 * i] = convert (f[i + 256]);
s16[6 * i + 1] = convert (f[i + 512]);
s16[6 * i + 2] = convert (f[i + 768]);
s16[6 * i + 3] = convert (f[i + 1024]);
s16[6 * i + 4] = 0;
s16[6 * i + 5] = convert (f[i]);
}
break;
case A52_3F2R | A52_LFE:
for (i = 0; i < 256; i++) {
s16[6 * i] = convert (f[i + 256]);
s16[6 * i + 1] = convert (f[i + 768]);
s16[6 * i + 2] = convert (f[i + 1024]);
s16[6 * i + 3] = convert (f[i + 1280]);
s16[6 * i + 4] = convert (f[i + 512]);
s16[6 * i + 5] = convert (f[i]);
}
break;
}
}
static int
gst_a52dec_channels (int flags)
gst_a52dec_channels (int flags, GstAudioChannelPosition ** pos)
{
int chans = 0;
/* allocated just for safety. Number makes no sense */
if (pos) {
*pos = g_new (GstAudioChannelPosition, 6);
}
if (flags & A52_LFE) {
chans += 1;
*pos[0] = GST_AUDIO_CHANNEL_POSITION_LFE;
}
flags &= A52_CHANNEL_MASK;
switch (flags) {
case A52_3F2R:
if (pos) {
*pos[0 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
*pos[1 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER;
*pos[2 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
*pos[3 + chans] = GST_AUDIO_CHANNEL_POSITION_REAR_LEFT;
*pos[4 + chans] = GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT;
}
chans += 5;
break;
case A52_2F2R:
if (pos) {
*pos[0 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
*pos[1 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
*pos[2 + chans] = GST_AUDIO_CHANNEL_POSITION_REAR_LEFT;
*pos[3 + chans] = GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT;
}
chans += 4;
break;
case A52_3F1R:
if (pos) {
*pos[0 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
*pos[1 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER;
*pos[2 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
*pos[3 + chans] = GST_AUDIO_CHANNEL_POSITION_REAR_CENTER;
}
chans += 4;
break;
case A52_2F1R:
case A52_3F:
if (pos) {
*pos[0 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
*pos[1 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
*pos[2 + chans] = GST_AUDIO_CHANNEL_POSITION_REAR_CENTER;
}
chans += 3;
case A52_CHANNEL:
break;
case A52_3F:
if (pos) {
*pos[0 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
*pos[1 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER;
*pos[2 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
}
chans += 3;
break;
/*case A52_CHANNEL: */
case A52_STEREO:
case A52_DOLBY:
if (pos) {
*pos[0 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
*pos[1 + chans] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
}
chans += 2;
break;
default:
/* error */
g_warning ("a52dec invalid flags %d", flags);
g_free (pos);
return 0;
}
return chans;
}
static int
gst_a52dec_push (GstPad * srcpad, int flags, sample_t * _samples,
gst_a52dec_push (GstPad * srcpad, int flags, sample_t * samples,
GstClockTime timestamp)
{
GstBuffer *buf;
int chans;
int chans, n, c;
#ifdef LIBA52_DOUBLE
float samples[256 * 6];
int i;
for (i = 0; i < 256 * 6; i++)
samples[i] = _samples[i];
#else
float *samples = _samples;
#endif
flags &= A52_CHANNEL_MASK | A52_LFE;
chans = gst_a52dec_channels (flags);
flags &= (A52_CHANNEL_MASK | A52_LFE);
chans = gst_a52dec_channels (flags, NULL);
if (!chans) {
return 1;
}
buf = gst_buffer_new ();
GST_BUFFER_SIZE (buf) = sizeof (int16_t) * 256 * chans;
GST_BUFFER_SIZE (buf) = 256 * chans * (SAMPLE_WIDTH / 8);
GST_BUFFER_DATA (buf) = g_malloc (GST_BUFFER_SIZE (buf));
for (n = 0; n < 256; n++) {
for (c = 0; c < chans; c++) {
((sample_t *) GST_BUFFER_DATA (buf))[n * chans + c] =
samples[c * 256 + n];
}
}
GST_BUFFER_TIMESTAMP (buf) = timestamp;
float_to_int (samples, (int16_t *) GST_BUFFER_DATA (buf), flags);
gst_pad_push (srcpad, GST_DATA (buf));
@ -348,18 +286,29 @@ gst_a52dec_push (GstPad * srcpad, int flags, sample_t * _samples,
/* END modified a52dec conversion code */
static void
gst_a52dec_reneg (GstPad * pad, int channels, int rate)
static gboolean
gst_a52dec_reneg (GstPad * pad)
{
GST_INFO ("a52dec: reneg channels:%d rate:%d\n", channels, rate);
GstAudioChannelPosition *pos;
GstA52Dec *a52dec = GST_A52DEC (gst_pad_get_parent (pad));
gint channels = gst_a52dec_channels (a52dec->using_channels, &pos);
GstCaps *caps;
gst_pad_set_explicit_caps (pad,
gst_caps_new_simple ("audio/x-raw-int",
"endianness", G_TYPE_INT, G_BYTE_ORDER,
"signed", G_TYPE_BOOLEAN, TRUE,
"width", G_TYPE_INT, 16,
"depth", G_TYPE_INT, 16,
"channels", G_TYPE_INT, channels, "rate", G_TYPE_INT, rate, NULL));
if (!channels)
return FALSE;
GST_INFO ("a52dec: reneg channels:%d rate:%d\n",
channels, a52dec->sample_rate);
caps = gst_caps_new_simple ("audio/x-raw-float",
"endianness", G_TYPE_INT, G_BYTE_ORDER,
"width", G_TYPE_INT, SAMPLE_WIDTH,
"channels", G_TYPE_INT, channels,
"rate", G_TYPE_INT, a52dec->sample_rate, NULL);
gst_audio_set_channel_positions (gst_caps_get_structure (caps, 0), pos);
g_free (pos);
return gst_pad_set_explicit_caps (pad, caps);
}
static void
@ -487,8 +436,8 @@ gst_a52dec_loop (GstElement * element)
if (need_reneg == TRUE) {
GST_DEBUG ("a52dec reneg: sample_rate:%d stream_chans:%d using_chans:%d\n",
a52dec->sample_rate, a52dec->stream_channels, a52dec->using_channels);
gst_a52dec_reneg (a52dec->srcpad,
gst_a52dec_channels (a52dec->using_channels), a52dec->sample_rate);
if (!gst_a52dec_reneg (a52dec->srcpad))
goto end;
}
if (a52dec->dynamic_range_compression == FALSE) {
@ -621,7 +570,7 @@ static gboolean
plugin_init (GstPlugin * plugin)
{
if (!gst_library_load ("gstbytestream"))
if (!gst_library_load ("gstbytestream") || !gst_library_load ("gstaudio"))
return FALSE;
if (!gst_element_register (plugin, "a52dec", GST_RANK_PRIMARY,

30
gst-libs/gst/audio/Makefile.am
View file

@ -1,15 +1,32 @@
# variables used for enum/marshal generation
glib_enum_headers=multichannel.h
glib_enum_define=GST_AUDIO
glib_enum_prefix=gst_audio
built_sources = multichannel-enumtypes.c
built_headers = multichannel-enumtypes.h
BUILT_SOURCES = $(built_sources) $(built_headers)
librarydir = $(libdir)/gstreamer-@GST_MAJORMINOR@
library_LTLIBRARIES = libgstaudio.la libgstaudiofilter.la
noinst_LTLIBRARIES = libgstaudiofilterexample.la
EXTRA_DIST = gstaudiofiltertemplate.c make_filter
CLEANFILES = gstaudiofilterexample.c
CLEANFILES = gstaudiofilterexample.c \
$(BUILT_SOURCES)
libgstaudio_la_SOURCES = audio.c audioclock.c
libgstaudio_la_SOURCES = audio.c audioclock.c \
multichannel.c
nodist_libgstaudio_la_SOURCES = $(built_sources)
libgstaudioincludedir = $(includedir)/gstreamer-@GST_MAJORMINOR@/gst/audio
libgstaudioinclude_HEADERS = audio.h audioclock.h gstaudiofilter.h
libgstaudioinclude_HEADERS = \
audio.h \
audioclock.h \
gstaudiofilter.h \
multichannel.h \
multichannel-enumtypes.h
libgstaudio_la_LIBADD =
libgstaudio_la_CFLAGS = $(GST_CFLAGS)
@ -25,3 +42,10 @@ libgstaudiofilterexample_la_LDFLAGS = $(GST_PLUGIN_LDFLAGS)
gstaudiofilterexample.c: $(srcdir)/make_filter $(srcdir)/gstaudiofiltertemplate.c
$(srcdir)/make_filter AudiofilterExample $(srcdir)/gstaudiofiltertemplate.c
noinst_PROGRAMS = testchannels
testchannels_SOURCES = testchannels.c
testchannels_CFLAGS = $(GST_CFLAGS)
testchannels_LDFLAGS = $(GST_LIBS)
include $(top_srcdir)/common/glib-gen.mak

3
gst-libs/gst/audio/audio.c
View file

@ -22,6 +22,7 @@
#endif
#include "audio.h"
#include "multichannel-enumtypes.h"
#include <gst/gststructure.h>
@ -267,6 +268,8 @@ gst_audio_structure_set_int (GstStructure * structure, GstAudioFieldFlag flag)
static gboolean
plugin_init (GstPlugin * plugin)
{
gst_audio_channel_position_get_type ();
return TRUE;
}

634
gst-libs/gst/audio/multichannel.c Normal file
View file

@ -0,0 +1,634 @@
/* GStreamer Multichannel-Audio helper functions
* (c) 2004 Ronald Bultje <rbultje@ronald.bitfreak.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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include "multichannel.h"
#define GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME "channel-positions"
/*
* This function checks if basic assumptions apply:
* - does each position occur at most once?
* - do conflicting positions occur?
* + front_mono vs. front_left/right
* + front_center vs. front_left/right_of_center
* + rear_center vs. rear_left/right
* It also adds some hacks that 0.8.x needs for compatibility:
* - if channels == 1, are we really mono?
* - if channels == 2, are we really stereo?
*/
static gboolean
gst_audio_check_channel_positions (const GstAudioChannelPosition * pos,
gint channels)
{
gint i, n;
struct
{
GstAudioChannelPosition pos1[2];
GstAudioChannelPosition pos2[1];
} conf[] = {
/* front: mono <-> stereo */
{ {
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT}, {
GST_AUDIO_CHANNEL_POSITION_FRONT_MONO}},
/* front center: 2 <-> 1 */
{ {
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER}, {
GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER}},
/* rear: 2 <-> 1 */
{ {
GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT}, {
GST_AUDIO_CHANNEL_POSITION_REAR_CENTER}}, { {
GST_AUDIO_CHANNEL_POSITION_INVALID}}
};
/* check for invalid channel positions */
for (n = 0; n < channels; n++) {
if (pos[n] == GST_AUDIO_CHANNEL_POSITION_INVALID) {
g_warning ("Position %d is invalid, not allowed", n);
return FALSE;
}
}
/* check for multiple position occurrences */
for (i = GST_AUDIO_CHANNEL_POSITION_INVALID + 1;
i < GST_AUDIO_CHANNEL_POSITION_NUM; i++) {
gint count = 0;
for (n = 0; n < channels; n++) {
if (pos[n] == i)
count++;
}
if (count > 1) {
g_warning ("Channel position %d occurred %d times, not allowed",
i, count);
return FALSE;
}
}
/* check for position conflicts */
for (i = 0; conf[i].pos1[0] != GST_AUDIO_CHANNEL_POSITION_INVALID; i++) {
gboolean found1 = FALSE, found2 = FALSE;
for (n = 0; n < channels; n++) {
if (pos[n] == conf[i].pos1[0] || pos[n] == conf[i].pos1[1])
found1 = TRUE;
else if (pos[n] == conf[i].pos2[0])
found2 = TRUE;
}
if (found1 && found2) {
g_warning ("Found conflicting channel positions %d/%d and %d",
conf[i].pos1[0], conf[i].pos1[1], conf[i].pos2[0]);
return FALSE;
}
}
/* 0.8.x evilry */
if ((channels == 1 && pos[0] != GST_AUDIO_CHANNEL_POSITION_FRONT_MONO) ||
(channels == 2 && (pos[0] != GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT ||
pos[1] != GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT))) {
g_warning ("0.8.x: channels=1 implies mono; channels=2 implies stereo");
return FALSE;
}
return TRUE;
}
/**
* gst_audio_get_channel_positions:
* @str: A #GstStructure to retrieve channel positions from.
*
* Retrieves a number of (fixed!) audio channel positions from
* the provided #GstStructure and returns it as a newly allocated
* array. The caller should g_free () this array. The caller
* should also check that the members in this #GstStructure are
* indeed "fixed" before calling this function.
*
* Returns: a newly allocated array containing the channel
* positions as provided in the given #GstStructure. Returns
* NULL on error.
*/
GstAudioChannelPosition *
gst_audio_get_channel_positions (GstStructure * str)
{
GstAudioChannelPosition *pos;
gint channels, n;
const GValue *pos_val_arr, *pos_val_entry;
gboolean res;
GType t;
/* get number of channels, general type checkups */
g_return_val_if_fail (str != NULL, NULL);
res = gst_structure_get_int (str, "channels", &channels);
g_return_val_if_fail (res, NULL);
g_return_val_if_fail (channels > 0, NULL);
pos_val_arr = gst_structure_get_value (str,
GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME);
/* The following checks are here to retain compatibility for plugins not
* implementing this property. They expect that channels=1 implies mono
* and channels=2 implies stereo, so we follow that.
* This might be removed during 0.9.x. */
if (!pos_val_arr && (channels == 1 || channels == 2)) {
pos = g_new (GstAudioChannelPosition, channels);
if (channels == 1) {
pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_MONO;
} else {
pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
pos[1] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
}
return pos;
}
g_return_val_if_fail (pos_val_arr != NULL, NULL);
g_return_val_if_fail (gst_value_list_get_size (pos_val_arr) == channels,
NULL);
for (n = 0; n < channels; n++) {
t = G_VALUE_TYPE (gst_value_list_get_value (pos_val_arr, n));
g_return_val_if_fail (t == GST_TYPE_AUDIO_CHANNEL_POSITION, NULL);
}
/* ... and fill array */
pos = g_new (GstAudioChannelPosition, channels);
for (n = 0; n < channels; n++) {
pos_val_entry = gst_value_list_get_value (pos_val_arr, n);
pos[n] = g_value_get_enum (pos_val_entry);
}
if (!gst_audio_check_channel_positions (pos, channels)) {
g_free (pos);
return NULL;
}
return pos;
}
/**
* gst_audio_set_channel_positions:
* @str: A #GstStructure to retrieve channel positions from.
* @pos: an array of channel positions. The number of members
* in this array should be equal to the (fixed!) number
* of the "channels" property in the given #GstStructure.
*
* Adds a "channel-positions" property to the given #GstStructure,
* which will represent the channel positions as given in the
* provided #GstAudioChannelPosition array.
*/
void
gst_audio_set_channel_positions (GstStructure * str,
const GstAudioChannelPosition * pos)
{
GValue pos_val_arr = { 0 }, pos_val_entry = {
0};
gint channels, n;
gboolean res;
/* get number of channels, checkups */
g_return_if_fail (str != NULL);
g_return_if_fail (pos != NULL);
res = gst_structure_get_int (str, "channels", &channels);
g_return_if_fail (res);
g_return_if_fail (channels > 0);
if (!gst_audio_check_channel_positions (pos, channels))
return;
/* build gvaluearray from positions */
g_value_init (&pos_val_entry, GST_TYPE_AUDIO_CHANNEL_POSITION);
g_value_init (&pos_val_arr, GST_TYPE_FIXED_LIST);
for (n = 0; n < channels; n++) {
g_value_set_enum (&pos_val_entry, pos[n]);
gst_value_list_append_value (&pos_val_arr, &pos_val_entry);
}
g_value_unset (&pos_val_entry);
/* add to structure */
gst_structure_set_value (str,
GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME, &pos_val_arr);
g_value_unset (&pos_val_arr);
}
/**
* gst_audio_set_structure_channel_positions_list:
* @str: #GstStructure to set the list of channel positions
* on.
* @pos: the array containing one or more possible audio
* channel positions that we should add in each value
* of the array in the given structure.
* @num_positions: the number of values in pos.
*
* Sets a (possibly non-fixed) list of possible audio channel
* positions (given in pos) on the given structure. The
* structure, after this function has been called, will contain
* a "channel-positions" property with an array of the size of
* the "channels" property value in the given structure (note
* that this means that the channels property in the provided
* structure should be fixed!). Each value in the array will
* contain each of the values given in the pos array.
*/
void
gst_audio_set_structure_channel_positions_list (GstStructure * str,
const GstAudioChannelPosition * pos, gint num_positions)
{
gint channels, n, c;
GValue pos_val_arr = { 0 }, pos_val_list = {
0}, pos_val_entry = {
0};
gboolean res;
/* get number of channels, general type checkups */
g_return_if_fail (str != NULL);
g_return_if_fail (num_positions > 0);
g_return_if_fail (pos != NULL);
res = gst_structure_get_int (str, "channels", &channels);
g_return_if_fail (res);
g_return_if_fail (channels > 0);
/* 0.8.x: channels=1 or channels=2 is mono/stereo, no positions needed
* there (we discard them anyway) */
if (channels == 1 || channels == 2)
return;
/* create the array of lists */
g_value_init (&pos_val_arr, GST_TYPE_FIXED_LIST);
g_value_init (&pos_val_entry, GST_TYPE_AUDIO_CHANNEL_POSITION);
for (n = 0; n < channels; n++) {
g_value_init (&pos_val_list, GST_TYPE_LIST);
for (c = 0; c < num_positions; c++) {
g_value_set_enum (&pos_val_entry, pos[c]);
gst_value_list_append_value (&pos_val_list, &pos_val_entry);
}
gst_value_list_append_value (&pos_val_arr, &pos_val_list);
g_value_unset (&pos_val_list);
}
g_value_unset (&pos_val_entry);
gst_structure_set_value (str, GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME,
&pos_val_arr);
g_value_unset (&pos_val_arr);
}
/*
* Helper function for below. The structure will be conserved,
* but might be cut down. Any additional structures that were
* created will be stored in the returned caps.
*/
static GstCaps *
add_list_to_struct (GstStructure * str,
const GstAudioChannelPosition * pos, gint num_positions)
{
GstCaps *caps = gst_caps_new_empty ();
const GValue *chan_val;
chan_val = gst_structure_get_value (str, "channels");
if (G_VALUE_TYPE (chan_val) == G_TYPE_INT) {
gst_audio_set_structure_channel_positions_list (str, pos, num_positions);
} else if (G_VALUE_TYPE (chan_val) == GST_TYPE_LIST) {
gint size;
const GValue *sub_val;
size = gst_value_list_get_size (chan_val);
sub_val = gst_value_list_get_value (chan_val, 0);
gst_structure_set_value (str, "channels", sub_val);
gst_caps_append (caps, add_list_to_struct (str, pos, num_positions));
while (--size > 0) {
str = gst_structure_copy (str);
sub_val = gst_value_list_get_value (chan_val, size);
gst_structure_set_value (str, "channels", sub_val);
gst_caps_append (caps, add_list_to_struct (str, pos, num_positions));
gst_caps_append_structure (caps, str);
}
} else if (G_VALUE_TYPE (chan_val) == GST_TYPE_INT_RANGE) {
gint min, max;
min = gst_value_get_int_range_min (chan_val);
max = gst_value_get_int_range_max (chan_val);
gst_structure_set (str, "channels", G_TYPE_INT, min, NULL);
gst_audio_set_structure_channel_positions_list (str, pos, num_positions);
for (++min; min < max; min++) {
str = gst_structure_copy (str);
gst_structure_set (str, "channels", G_TYPE_INT, min, NULL);
gst_audio_set_structure_channel_positions_list (str, pos, num_positions);
gst_caps_append_structure (caps, str);
}
} else {
g_warning ("Unknown value type for channels property");
}
return caps;
}
/**
* gst_audio_set_caps_channel_positions_list:
* @caps: #GstCaps to set the list of channel positions on.
* @pos: the array containing one or more possible audio
* channel positions that we should add in each value
* of the array in the given structure.
* @num_positions: the number of values in pos.
*
* Sets a (possibly non-fixed) list of possible audio channel
* positions (given in pos) on the given caps. Each of the
* structures of the caps, after this function has been called,
* will contain a "channel-positions" property with an array.
* Each value in the array will contain each of the values given
* in the pos array. Note that the size of the caps might be
* increased by this, since each structure with a "channel-
* positions" property needs to have a fixed "channels" property.
* The input caps is not required to have this.
*/
void
gst_audio_set_caps_channel_positions_list (GstCaps * caps,
const GstAudioChannelPosition * pos, gint num_positions)
{
gint size, n;
/* get number of channels, general type checkups */
g_return_if_fail (caps != NULL);
g_return_if_fail (num_positions > 0);
g_return_if_fail (pos != NULL);
size = gst_caps_get_size (caps);
for (n = 0; n < size; n++) {
gst_caps_append (caps, add_list_to_struct (gst_caps_get_structure (caps,
n), pos, num_positions));
}
}
/**
* gst_audio_fixate_channel_positions:
* @str: a #GstStructure containing a (possibly unfixed)
* "channel-positions" property.
*
* Custom fixate function. Elements that implement some sort of
* channel conversion algorhithm should use this function for
* fixating on GstAudioChannelPosition properties. It will take
* care of equal channel positioning (left/right). Caller g_free()s
* the return value. The input properties may be (and are supposed
* to be) unfixed.
* Note that this function is mostly a hack because we currently
* have no way to add default fixation functions for new GTypes.
*
* Returns: fixed values that the caller could use as a fixed
* set of #GstAudioChannelPosition values.
*/
GstAudioChannelPosition *
gst_audio_fixate_channel_positions (GstStructure * str)
{
GstAudioChannelPosition *pos;
gint channels, n, num_unfixed = 0, i, c;
const GValue *pos_val_arr, *pos_val_entry, *pos_val;
gboolean res, is_stereo = TRUE;
GType t;
/*
* We're going to do this cluelessly. We'll make an array of values that
* conflict with each other and, for each iteration in this array, pick
* either one until all unknown values are filled. This might not work in
* corner cases but should work OK for the general case.
*/
struct
{
GstAudioChannelPosition pos1[2];
GstAudioChannelPosition pos2[1];
} conf[] = {
/* front: mono <-> stereo */
{ {
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT}, {
GST_AUDIO_CHANNEL_POSITION_FRONT_MONO}},
/* front center: 2 <-> 1 */
{ {
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER}, {
GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER}},
/* rear: 2 <-> 1 */
{ {
GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT}, {
GST_AUDIO_CHANNEL_POSITION_REAR_CENTER}}, { {
GST_AUDIO_CHANNEL_POSITION_INVALID, GST_AUDIO_CHANNEL_POSITION_INVALID}, {
GST_AUDIO_CHANNEL_POSITION_LFE}}, { {
GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT,
GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT}, {
GST_AUDIO_CHANNEL_POSITION_INVALID}}, { {
GST_AUDIO_CHANNEL_POSITION_INVALID, GST_AUDIO_CHANNEL_POSITION_INVALID}, {
GST_AUDIO_CHANNEL_POSITION_INVALID}}
};
struct
{
gint num_opt[3];
guint num_opts[3];
gboolean is_fixed[3];
gint choice; /* -1 is none, 0 is the two, 1 is the one */
} opt;
/* get number of channels, general type checkups */
g_return_val_if_fail (str != NULL, NULL);
res = gst_structure_get_int (str, "channels", &channels);
g_return_val_if_fail (res, NULL);
g_return_val_if_fail (channels > 0, NULL);
/* 0.8.x mono/stereo checks */
pos_val_arr = gst_structure_get_value (str,
GST_AUDIO_CHANNEL_POSITIONS_PROPERTY_NAME);
if (!pos_val_arr && (channels == 1 || channels == 2)) {
pos = g_new (GstAudioChannelPosition, channels);
if (channels == 1) {
pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_MONO;
} else {
pos[0] = GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT;
pos[1] = GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT;
}
return pos;
}
g_return_val_if_fail (pos_val_arr != NULL, NULL);
g_return_val_if_fail (gst_value_list_get_size (pos_val_arr) == channels,
NULL);
for (n = 0; n < channels; n++) {
t = G_VALUE_TYPE (gst_value_list_get_value (pos_val_arr, n));
g_return_val_if_fail (t == GST_TYPE_LIST ||
t == GST_TYPE_AUDIO_CHANNEL_POSITION, NULL);
}
/* all unknown, to start with */
pos = g_new (GstAudioChannelPosition, channels);
for (n = 0; n < channels; n++)
pos[n] = GST_AUDIO_CHANNEL_POSITION_INVALID;
num_unfixed = channels;
/* Iterate the array of conflicting values */
for (i = 0; conf[i].pos1[0] != GST_AUDIO_CHANNEL_POSITION_INVALID ||
conf[i].pos2[0] != GST_AUDIO_CHANNEL_POSITION_INVALID; i++) {
/* front/center only important if not mono (obviously) */
if (conf[i].pos1[0] == GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER &&
!is_stereo)
continue;
/* init values */
for (n = 0; n < 3; n++) {
opt.num_opt[n] = -1;
opt.num_opts[n] = -1;
opt.is_fixed[n] = FALSE;
}
/* Now, we'll see for each channel if it allows for any of the values in
* the set of conflicting audio channel positions and keep scores. */
for (n = 0; n < channels; n++) {
/* if the channel is already taken, don't bother */
if (pos[n] != GST_AUDIO_CHANNEL_POSITION_INVALID)
continue;
pos_val_entry = gst_value_list_get_value (pos_val_arr, n);
t = G_VALUE_TYPE (pos_val_entry);
if (t == GST_TYPE_LIST) {
/* This algorhythm is suboptimal. */
for (c = 0; c < gst_value_list_get_size (pos_val_entry); c++) {
pos_val = gst_value_list_get_value (pos_val_entry, c);
if (g_value_get_enum (pos_val) == conf[i].pos1[0] &&
opt.num_opts[0] > gst_value_list_get_size (pos_val_entry) &&
!opt.is_fixed[0]) {
/* Now test if the old position of num_opt[0] also allows for
* the other channel (which was skipped previously). If so,
* keep score. */
if (opt.num_opt[0] != -1) {
gint c1;
pos_val_entry = gst_value_list_get_value (pos_val_arr,
opt.num_opt[0]);
if (G_VALUE_TYPE (pos_val_entry) == GST_TYPE_LIST) {
for (c1 = 0; c1 < gst_value_list_get_size (pos_val_entry); c1++) {
pos_val = gst_value_list_get_value (pos_val_entry, c1);
if (g_value_get_enum (pos_val) == conf[i].pos1[1] &&
opt.num_opts[1] > opt.num_opts[0] && !opt.is_fixed[1]) {
opt.num_opts[1] = opt.num_opts[0];
opt.num_opt[1] = opt.num_opt[0];
}
}
pos_val = gst_value_list_get_value (pos_val_entry, c);
}
pos_val_entry = gst_value_list_get_value (pos_val_arr, n);
}
/* and save values */
opt.num_opts[0] = gst_value_list_get_size (pos_val_entry);
opt.num_opt[0] = n;
} else if (g_value_get_enum (pos_val) == conf[i].pos1[1] &&
opt.num_opts[1] > gst_value_list_get_size (pos_val_entry) &&
!opt.is_fixed[1] && n != opt.num_opt[0]) {
opt.num_opts[1] = gst_value_list_get_size (pos_val_entry);
opt.num_opt[1] = n;
}
/* 2 goes separately, because 0/1 vs. 2 are separate */
if (g_value_get_enum (pos_val) == conf[i].pos2[0] &&
opt.num_opts[2] > gst_value_list_get_size (pos_val_entry) &&
!opt.is_fixed[2]) {
opt.num_opts[2] = gst_value_list_get_size (pos_val_entry);
opt.num_opt[2] = n;
}
}
} else {
if (g_value_get_enum (pos_val_entry) == conf[i].pos1[0]) {
opt.num_opt[0] = n;
opt.is_fixed[0] = TRUE;
} else if (g_value_get_enum (pos_val_entry) == conf[i].pos1[1]) {
opt.num_opt[1] = n;
opt.is_fixed[1] = TRUE;
} else if (g_value_get_enum (pos_val_entry) == conf[i].pos2[0]) {
opt.num_opt[2] = n;
opt.is_fixed[2] = TRUE;
}
}
}
/* check our results and choose either one */
if ((opt.is_fixed[0] || opt.is_fixed[1]) && opt.is_fixed[2]) {
g_warning ("Pre-fixated on both %d/%d and %d - conflict!",
conf[i].pos1[0], conf[i].pos1[1], conf[i].pos2[0]);
g_free (pos);
return NULL;
} else if ((opt.is_fixed[0] && opt.num_opt[1] == -1) ||
(opt.is_fixed[1] && opt.num_opt[0] == -1)) {
g_warning ("Pre-fixated one side, but other side n/a of %d/%d",
conf[i].pos1[0], conf[i].pos1[1]);
g_free (pos);
return NULL;
} else if (opt.is_fixed[0] || opt.is_fixed[1]) {
opt.choice = 0;
} else if (opt.is_fixed[2]) {
opt.choice = 1;
} else if (opt.num_opt[0] != -1 && opt.num_opt[1] != -1) {
opt.choice = 0;
} else if (opt.num_opt[2] != -1) {
opt.choice = 1;
} else {
opt.choice = -1;
}
/* stereo? Note that we keep is_stereo to TRUE if we didn't decide on
* any arrangement. The mono/stereo channels might be handled elsewhere
* which is clearly outside the scope of this element, so we cannot
* know and expect the application to handle that then. */
if (conf[i].pos2[0] == GST_AUDIO_CHANNEL_POSITION_FRONT_MONO &&
opt.choice == 1) {
is_stereo = FALSE;
}
/* now actually decide what we'll do and fixate on that */
if (opt.choice == 0) {
g_assert (conf[i].pos1[0] != GST_AUDIO_CHANNEL_POSITION_INVALID &&
conf[i].pos1[1] != GST_AUDIO_CHANNEL_POSITION_INVALID);
pos[opt.num_opt[0]] = conf[i].pos1[0];
pos[opt.num_opt[1]] = conf[i].pos1[1];
num_unfixed -= 2;
} else if (opt.choice == 1) {
g_assert (conf[i].pos2[0] != GST_AUDIO_CHANNEL_POSITION_INVALID);
pos[opt.num_opt[2]] = conf[i].pos2[0];
num_unfixed--;
}
}
/* safety check */
if (num_unfixed > 0) {
g_warning ("%d unfixed channel positions left after fixation!",
num_unfixed);
g_free (pos);
return NULL;
}
if (!gst_audio_check_channel_positions (pos, channels)) {
g_free (pos);
return NULL;
}
return pos;
}

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/* GStreamer Multichannel-Audio helper functions
* (c) 2004 Ronald Bultje <rbultje@ronald.bitfreak.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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifndef __GST_AUDIO_MULTICHANNEL_H__
#define __GST_AUDIO_MULTICHANNEL_H__
#include <gst/audio/audio.h>
#include <gst/audio/multichannel-enumtypes.h>
typedef enum {
GST_AUDIO_CHANNEL_POSITION_INVALID = -1,
/* Main front speakers. Mono and left/right are mututally exclusive! */
GST_AUDIO_CHANNEL_POSITION_FRONT_MONO,
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
/* rear. Left/right and center are mututally exclusive! */
GST_AUDIO_CHANNEL_POSITION_REAR_CENTER,
GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
/* subwoofer/low-frequency */
GST_AUDIO_CHANNEL_POSITION_LFE,
/* Center front speakers. Center and left/right_of_center cannot be
* used together! */
GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER,
GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
/* sides */
GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT,
GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT,
/* don't use - counter */
GST_AUDIO_CHANNEL_POSITION_NUM
} GstAudioChannelPosition;
/* Retrieves or sets the positions from/to a GstStructure. Only
* works with fixed caps, caller should check for that! Caller
* g_free()s result of the getter. */
GstAudioChannelPosition *
gst_audio_get_channel_positions (GstStructure *str);
void gst_audio_set_channel_positions (GstStructure *str,
const GstAudioChannelPosition *pos);
/* Sets a (non-fixed) list of possible audio channel positions
* on a structure (this requires the "channels" property to
* be fixed!) or on a caps (here, the "channels" property may be
* unfixed and the caps may even contain multiple structures). */
void gst_audio_set_structure_channel_positions_list
(GstStructure *str,
const GstAudioChannelPosition *pos,
gint num_positions);
void gst_audio_set_caps_channel_positions_list
(GstCaps *caps,
const GstAudioChannelPosition *pos,
gint num_positions);
/* Custom fixate function. Elements that implement some sort of
* channel conversion algorhithm should use this function for
* fixating on GstAudioChannelPosition properties. It will take
* care of equal channel positioning (left/right). Caller g_free()s
* the return value. The input properties may be (and are supposed
* to be) unfixed. */
GstAudioChannelPosition *
gst_audio_fixate_channel_positions (GstStructure *str);
#endif /* __GST_AUDIO_MULTICHANNEL_H__ */

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gst-libs/gst/audio/testchannels.c Normal file
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/* GStreamer Multichannel Test
* (c) 2004 Ronald Bultje <rbultje@ronald.bitfreak.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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <gst/gst.h>
#include <multichannel.c>
#include <multichannel-enumtypes.c>
gint
main (gint argc, gchar * argv[])
{
gchar *str;
GstCaps *caps;
GstAudioChannelPosition pos[2] = { GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT
};
/* register multichannel type */
gst_init (&argc, &argv);
gst_audio_channel_position_get_type ();
/* test some caps-string conversions */
caps = gst_caps_new_simple ("audio/x-raw-int",
"channels", G_TYPE_INT, 2, NULL);
str = gst_caps_to_string (caps);
g_print ("Test caps #1: %s\n", str);
g_free (str);
gst_audio_set_channel_positions (gst_caps_get_structure (caps, 0), pos);
str = gst_caps_to_string (caps);
g_print ("Test caps #2: %s\n", str);
g_free (str);
gst_caps_free (caps);
return 0;
}