gstreamer/ext/vorbis/vorbisfile.c
Wim Taymans 4ff636bad3 - implement eventmasks/format/querytype functions
Original commit message from CVS:
- implement eventmasks/format/querytype functions
- added convert functions
- added seek on bytes
2002-07-24 21:40:16 +00:00

789 lines
21 KiB
C

/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
*
* 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.
*/
#include <string.h>
#include <gst/gst.h>
#include <vorbis/codec.h>
#include <vorbis/vorbisfile.h>
#include <gst/bytestream/bytestream.h>
#define GST_TYPE_VORBISFILE \
(vorbisfile_get_type())
#define GST_VORBISFILE(obj) \
(G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_VORBISFILE,VorbisFile))
#define GST_VORBISFILE_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_VORBISFILE,VorbisFileClass))
#define GST_IS_VORBISFILE(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_VORBISFILE))
#define GST_IS_VORBISFILE_CLASS(obj) \
(G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_VORBISFILE))
typedef struct _VorbisFile VorbisFile;
typedef struct _VorbisFileClass VorbisFileClass;
struct _VorbisFile {
GstElement element;
GstPad *sinkpad,*srcpad;
GstByteStream *bs;
OggVorbis_File vf;
gint current_section;
gboolean restart;
gboolean need_discont;
gboolean eos;
gboolean seek_pending;
gint64 seek_value;
GstFormat seek_format;
gboolean seek_accurate;
gboolean may_eos;
int16_t convsize;
guint64 total_out;
guint64 total_bytes;
guint64 offset;
};
struct _VorbisFileClass {
GstElementClass parent_class;
};
GType vorbisfile_get_type(void);
extern GstPadTemplate *dec_src_template, *dec_sink_template;
/* elementfactory information */
GstElementDetails vorbisfile_details =
{
"Ogg Vorbis decoder",
"Codec/Audio/Decoder",
"Decodes OGG Vorbis audio using the vorbisfile API",
VERSION,
"Monty <monty@xiph.org>, "
"Wim Taymans <wim.taymans@chello.be>",
"(C) 2000",
};
/* VorbisFile signals and args */
enum
{
/* FILL ME */
LAST_SIGNAL
};
enum
{
ARG_0,
ARG_COMMENT,
ARG_VENDOR,
ARG_VERSION,
ARG_CHANNELS,
ARG_RATE,
ARG_BITRATE_UPPER,
ARG_BITRATE_NOMINAL,
ARG_BITRATE_LOWER,
ARG_BITRATE_WINDOW,
};
static void gst_vorbisfile_class_init (VorbisFileClass *klass);
static void gst_vorbisfile_init (VorbisFile *vorbisfile);
static GstElementStateReturn
gst_vorbisfile_change_state (GstElement *element);
static const GstFormat* gst_vorbisfile_get_formats (GstPad *pad);
static gboolean gst_vorbisfile_src_convert (GstPad *pad, GstFormat src_format, gint64 src_value,
GstFormat *dest_format, gint64 *dest_value);
static const GstPadQueryType*
gst_vorbisfile_get_query_types (GstPad *pad);
static gboolean gst_vorbisfile_src_query (GstPad *pad, GstPadQueryType type,
GstFormat *format, gint64 *value);
static const GstEventMask*
gst_vorbisfile_get_event_masks (GstPad *pad);
static gboolean gst_vorbisfile_src_event (GstPad *pad, GstEvent *event);
static void gst_vorbisfile_get_property (GObject *object, guint prop_id,
GValue *value, GParamSpec *pspec);
static void gst_vorbisfile_loop (GstElement *element);
static GstElementClass *parent_class = NULL;
/*static guint gst_vorbisfile_signals[LAST_SIGNAL] = { 0 }; */
GType
vorbisfile_get_type (void)
{
static GType vorbisfile_type = 0;
if (!vorbisfile_type) {
static const GTypeInfo vorbisfile_info = {
sizeof (VorbisFileClass),
NULL,
NULL,
(GClassInitFunc) gst_vorbisfile_class_init,
NULL,
NULL,
sizeof (VorbisFile),
0,
(GInstanceInitFunc) gst_vorbisfile_init,
};
vorbisfile_type = g_type_register_static (GST_TYPE_ELEMENT, "VorbisFile", &vorbisfile_info, 0);
}
return vorbisfile_type;
}
static void
gst_vorbisfile_class_init (VorbisFileClass * klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass*) klass;
gstelement_class = (GstElementClass *) klass;
parent_class = g_type_class_ref (GST_TYPE_ELEMENT);
g_object_class_install_property (gobject_class, ARG_COMMENT,
g_param_spec_string ("comment", "Comment", "The comment tags for this vorbis stream",
"", G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_VENDOR,
g_param_spec_string ("vendor", "Vendor", "The vendor for this vorbis stream",
"", G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_VERSION,
g_param_spec_int ("version", "Version", "The version",
0, G_MAXINT, 0, G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_CHANNELS,
g_param_spec_int ("channels", "Channels", "The number of channels",
0, G_MAXINT, 0, G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_RATE,
g_param_spec_int ("rate", "Rate", "The samplerate",
0, G_MAXINT, 0, G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_BITRATE_UPPER,
g_param_spec_int ("bitrate_upper", "bitrate_upper", "bitrate_upper",
0, G_MAXINT, 0, G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_BITRATE_NOMINAL,
g_param_spec_int ("bitrate_nominal", "bitrate_nominal", "bitrate_nominal",
0, G_MAXINT, 0, G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_BITRATE_LOWER,
g_param_spec_int ("bitrate_lower", "bitrate_lower", "bitrate_lower",
0, G_MAXINT, 0, G_PARAM_READABLE));
g_object_class_install_property (gobject_class, ARG_BITRATE_WINDOW,
g_param_spec_int ("bitrate_window", "bitrate_window", "bitrate_window",
0, G_MAXINT, 0, G_PARAM_READABLE));
gobject_class->get_property = gst_vorbisfile_get_property;
gstelement_class->change_state = gst_vorbisfile_change_state;
}
static void
gst_vorbisfile_init (VorbisFile * vorbisfile)
{
vorbisfile->sinkpad = gst_pad_new_from_template (dec_sink_template, "sink");
gst_element_add_pad (GST_ELEMENT (vorbisfile), vorbisfile->sinkpad);
gst_pad_set_convert_function (vorbisfile->sinkpad, NULL);
gst_element_set_loop_function (GST_ELEMENT (vorbisfile), gst_vorbisfile_loop);
vorbisfile->srcpad = gst_pad_new_from_template (dec_src_template, "src");
gst_element_add_pad (GST_ELEMENT (vorbisfile), vorbisfile->srcpad);
gst_pad_set_formats_function (vorbisfile->srcpad, gst_vorbisfile_get_formats);
gst_pad_set_query_type_function (vorbisfile->srcpad, gst_vorbisfile_get_query_types);
gst_pad_set_query_function (vorbisfile->srcpad, gst_vorbisfile_src_query);
gst_pad_set_event_mask_function (vorbisfile->srcpad, gst_vorbisfile_get_event_masks);
gst_pad_set_event_function (vorbisfile->srcpad, gst_vorbisfile_src_event);
gst_pad_set_convert_function (vorbisfile->srcpad, gst_vorbisfile_src_convert);
vorbisfile->convsize = 4096;
vorbisfile->total_out = 0;
vorbisfile->total_bytes = 0;
vorbisfile->offset = 0;
vorbisfile->seek_pending = 0;
vorbisfile->need_discont = FALSE;
}
static size_t
gst_vorbisfile_read (void *ptr, size_t size, size_t nmemb, void *datasource)
{
guint32 got_bytes = 0;
guint8 *data;
size_t read_size = size * nmemb;
VorbisFile *vorbisfile = GST_VORBISFILE (datasource);
GST_DEBUG (0, "read %d", read_size);
/* make sure we don't go to EOS */
if (!vorbisfile->may_eos && vorbisfile->total_bytes &&
vorbisfile->offset + read_size > vorbisfile->total_bytes)
{
read_size = vorbisfile->total_bytes - vorbisfile->offset;
}
if (read_size == 0 || vorbisfile->eos)
return 0;
while (got_bytes == 0) {
got_bytes = gst_bytestream_peek_bytes (vorbisfile->bs, &data, read_size);
if (got_bytes < read_size) {
GstEvent *event;
guint32 avail;
gst_bytestream_get_status (vorbisfile->bs, &avail, &event);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_EOS:
GST_DEBUG (0, "eos");
vorbisfile->eos = TRUE;
if (avail == 0) {
gst_event_unref (event);
return 0;
}
break;
case GST_EVENT_DISCONTINUOUS:
GST_DEBUG (0, "discont");
vorbisfile->need_discont = TRUE;
default:
break;
}
gst_event_unref (event);
if (avail > 0)
got_bytes = gst_bytestream_peek_bytes (vorbisfile->bs, &data, avail);
else
got_bytes = 0;
}
}
memcpy (ptr, data, got_bytes);
gst_bytestream_flush_fast (vorbisfile->bs, got_bytes);
vorbisfile->offset += got_bytes;
return got_bytes / size;
}
static int
gst_vorbisfile_seek (void *datasource, int64_t offset, int whence)
{
VorbisFile *vorbisfile = GST_VORBISFILE (datasource);
GstSeekType method;
guint64 pending_offset = vorbisfile->offset;
gboolean need_total = FALSE;
if (!vorbisfile->vf.seekable) {
return -1;
}
GST_DEBUG (0, "seek %lld %d", offset, whence);
if (whence == SEEK_SET) {
method = GST_SEEK_METHOD_SET;
pending_offset = offset;
}
else if (whence == SEEK_CUR) {
method = GST_SEEK_METHOD_CUR;
pending_offset += offset;
}
else if (whence == SEEK_END) {
method = GST_SEEK_METHOD_END;
need_total = TRUE;
pending_offset = vorbisfile->total_bytes - offset;
}
else
return -1;
if (!gst_bytestream_seek (vorbisfile->bs, offset, method))
return -1;
vorbisfile->offset = pending_offset;
if (need_total)
vorbisfile->total_bytes = gst_bytestream_tell (vorbisfile->bs) + offset;
return 0;
}
static int
gst_vorbisfile_close (void *datasource)
{
GST_DEBUG (0, "close");
return 0;
}
static long
gst_vorbisfile_tell (void *datasource)
{
VorbisFile *vorbisfile = GST_VORBISFILE (datasource);
long result;
result = gst_bytestream_tell (vorbisfile->bs);
GST_DEBUG (0, "tell %ld", result);
return result;
}
ov_callbacks vorbisfile_ov_callbacks =
{
gst_vorbisfile_read,
gst_vorbisfile_seek,
gst_vorbisfile_close,
gst_vorbisfile_tell,
};
static void
gst_vorbisfile_loop (GstElement *element)
{
VorbisFile *vorbisfile = GST_VORBISFILE (element);
GstBuffer *outbuf;
long ret;
if (vorbisfile->restart) {
vorbisfile->current_section = 0;
vorbisfile->offset = 0;
vorbisfile->total_bytes = 0;
vorbisfile->may_eos = FALSE;
vorbisfile->vf.seekable = gst_bytestream_seek (vorbisfile->bs, 0, GST_SEEK_METHOD_SET);
if (ov_open_callbacks (vorbisfile, &vorbisfile->vf, NULL, 0, vorbisfile_ov_callbacks) < 0) {
gst_element_error (element, "this is not a vorbis file");
return;
}
vorbisfile->need_discont = TRUE;
vorbisfile->restart = FALSE;
}
if (vorbisfile->seek_pending) {
switch (vorbisfile->seek_format) {
case GST_FORMAT_TIME:
if (vorbisfile->seek_accurate) {
if (ov_time_seek (&vorbisfile->vf, (gdouble) vorbisfile->seek_value / GST_SECOND) == 0) {
vorbisfile->need_discont = TRUE;
}
}
else {
if (ov_time_seek_page (&vorbisfile->vf, (gdouble) vorbisfile->seek_value / GST_SECOND) == 0) {
vorbisfile->need_discont = TRUE;
}
}
break;
case GST_FORMAT_UNITS:
if (vorbisfile->seek_accurate) {
if (ov_pcm_seek (&vorbisfile->vf, (gdouble) vorbisfile->seek_value / GST_SECOND) == 0) {
vorbisfile->need_discont = TRUE;
}
}
else {
if (ov_pcm_seek_page (&vorbisfile->vf, (gdouble) vorbisfile->seek_value / GST_SECOND) == 0) {
vorbisfile->need_discont = TRUE;
}
}
break;
default:
break;
}
vorbisfile->seek_pending = FALSE;
}
if (vorbisfile->need_discont) {
GstEvent *discont;
GstClockTime time;
gint64 samples;
/* get stream stats */
time = (gint64) (ov_time_tell (&vorbisfile->vf) * GST_SECOND);
samples = (gint64) (ov_pcm_tell (&vorbisfile->vf));
discont = gst_event_new_discontinuous (FALSE, GST_FORMAT_TIME, time,
GST_FORMAT_UNITS, samples, NULL);
vorbisfile->need_discont = FALSE;
gst_pad_push (vorbisfile->srcpad, GST_BUFFER (discont));
}
outbuf = gst_buffer_new ();
GST_BUFFER_DATA (outbuf) = g_malloc (4096);
GST_BUFFER_SIZE (outbuf) = 4096;
ret = ov_read (&vorbisfile->vf, GST_BUFFER_DATA (outbuf), GST_BUFFER_SIZE (outbuf),
0, 2, 1, &vorbisfile->current_section);
if (ret == 0) {
GST_DEBUG (0, "eos");
//ov_clear (&vorbisfile->vf);
vorbisfile->restart = TRUE;
gst_buffer_unref (outbuf);
gst_pad_push (vorbisfile->srcpad, GST_BUFFER (gst_event_new (GST_EVENT_EOS)));
gst_element_set_eos (element);
return;
}
else if (ret < 0) {
g_warning ("vorbisfile: decoding error");
gst_buffer_unref (outbuf);
}
else {
GST_BUFFER_SIZE (outbuf) = ret;
if (!GST_PAD_CAPS (vorbisfile->srcpad)) {
vorbis_info *vi = ov_info (&vorbisfile->vf, -1);
gst_pad_try_set_caps (vorbisfile->srcpad,
GST_CAPS_NEW ("vorbisdec_src",
"audio/raw",
"format", GST_PROPS_STRING ("int"),
"law", GST_PROPS_INT (0),
"endianness", GST_PROPS_INT (G_BYTE_ORDER),
"signed", GST_PROPS_BOOLEAN (TRUE),
"width", GST_PROPS_INT (16),
"depth", GST_PROPS_INT (16),
"rate", GST_PROPS_INT (vi->rate),
"channels", GST_PROPS_INT (vi->channels)
));
}
vorbisfile->may_eos = TRUE;
{
GstFormat format;
gint64 value;
format = GST_FORMAT_TIME;
gst_vorbisfile_src_query (vorbisfile->srcpad, GST_PAD_QUERY_POSITION, &format, &value);
GST_BUFFER_TIMESTAMP (outbuf) = value;
}
if (!vorbisfile->vf.seekable) {
vorbisfile->total_bytes += GST_BUFFER_SIZE (outbuf);
}
if (GST_PAD_IS_CONNECTED (vorbisfile->srcpad)) {
gst_pad_push (vorbisfile->srcpad, outbuf);
}
else {
gst_buffer_unref (outbuf);
}
}
}
static const GstFormat*
gst_vorbisfile_get_formats (GstPad *pad)
{
static const GstFormat formats[] = {
GST_FORMAT_TIME,
GST_FORMAT_BYTES,
GST_FORMAT_UNITS,
0
};
return formats;
}
static gboolean
gst_vorbisfile_src_convert (GstPad *pad, GstFormat src_format, gint64 src_value,
GstFormat *dest_format, gint64 *dest_value)
{
gboolean res = TRUE;
guint scale = 1;
gint bytes_per_sample;
VorbisFile *vorbisfile;
vorbis_info *vi;
vorbisfile = GST_VORBISFILE (gst_pad_get_parent (pad));
vi = ov_info (&vorbisfile->vf, -1);
bytes_per_sample = vi->channels * 2;
switch (src_format) {
case GST_FORMAT_BYTES:
switch (*dest_format) {
case GST_FORMAT_UNITS:
*dest_value = src_value / (vi->channels * 2);
break;
case GST_FORMAT_DEFAULT:
*dest_format = GST_FORMAT_TIME;
case GST_FORMAT_TIME:
{
gint byterate = bytes_per_sample * vi->rate;
if (byterate == 0)
return FALSE;
*dest_value = src_value * GST_SECOND / byterate;
break;
}
default:
res = FALSE;
}
case GST_FORMAT_UNITS:
switch (*dest_format) {
case GST_FORMAT_BYTES:
*dest_value = src_value * bytes_per_sample;
break;
case GST_FORMAT_DEFAULT:
*dest_format = GST_FORMAT_TIME;
case GST_FORMAT_TIME:
if (vi->rate == 0)
return FALSE;
*dest_value = src_value * GST_SECOND / vi->rate;
break;
default:
res = FALSE;
}
break;
case GST_FORMAT_TIME:
switch (*dest_format) {
case GST_FORMAT_DEFAULT:
*dest_format = GST_FORMAT_BYTES;
case GST_FORMAT_BYTES:
scale = bytes_per_sample;
case GST_FORMAT_UNITS:
*dest_value = src_value * scale * vi->rate / GST_SECOND;
break;
default:
res = FALSE;
}
break;
default:
res = FALSE;
break;
}
return res;
}
static const GstPadQueryType*
gst_vorbisfile_get_query_types (GstPad *pad)
{
static const GstPadQueryType types[] = {
GST_PAD_QUERY_TOTAL,
GST_PAD_QUERY_POSITION,
0
};
return types;
}
static gboolean
gst_vorbisfile_src_query (GstPad *pad, GstPadQueryType type,
GstFormat *format, gint64 *value)
{
gboolean res = TRUE;
VorbisFile *vorbisfile;
vorbis_info *vi;
vorbisfile = GST_VORBISFILE (gst_pad_get_parent (pad));
vi = ov_info (&vorbisfile->vf, -1);
switch (type) {
case GST_PAD_QUERY_TOTAL:
{
switch (*format) {
case GST_FORMAT_UNITS:
if (vorbisfile->vf.seekable)
*value = ov_pcm_total (&vorbisfile->vf, -1);
else
return FALSE;
break;
case GST_FORMAT_BYTES:
if (vorbisfile->vf.seekable)
*value = ov_pcm_total (&vorbisfile->vf, -1) * vi->channels * 2;
else
return FALSE;
break;
case GST_FORMAT_DEFAULT:
*format = GST_FORMAT_TIME;
/* fall through */
case GST_FORMAT_TIME:
if (vorbisfile->vf.seekable)
*value = (gint64) (ov_time_total (&vorbisfile->vf, -1) * GST_SECOND);
else
return FALSE;
break;
default:
res = FALSE;
break;
}
break;
}
case GST_PAD_QUERY_POSITION:
switch (*format) {
case GST_FORMAT_DEFAULT:
*format = GST_FORMAT_TIME;
/* fall through */
case GST_FORMAT_TIME:
if (vorbisfile->vf.seekable)
*value = (gint64) (ov_time_tell (&vorbisfile->vf) * GST_SECOND);
else
*value = vorbisfile->total_bytes * GST_SECOND / (vi->rate * vi->channels * 2);
break;
case GST_FORMAT_BYTES:
if (vorbisfile->vf.seekable)
*value = ov_pcm_tell (&vorbisfile->vf) * vi->channels * 2;
else
*value = vorbisfile->total_bytes;
break;
case GST_FORMAT_UNITS:
if (vorbisfile->vf.seekable)
*value = ov_pcm_tell (&vorbisfile->vf);
else
*value = vorbisfile->total_bytes / (vi->channels * 2);
break;
default:
res = FALSE;
break;
}
break;
default:
res = FALSE;
break;
}
return res;
}
static const GstEventMask*
gst_vorbisfile_get_event_masks (GstPad *pad)
{
static const GstEventMask masks[] = {
{ GST_EVENT_SEEK, GST_SEEK_METHOD_SET | GST_SEEK_FLAG_ACCURATE },
{ 0, }
};
return masks;
}
static gboolean
gst_vorbisfile_src_event (GstPad *pad, GstEvent *event)
{
gboolean res = TRUE;
VorbisFile *vorbisfile;
vorbisfile = GST_VORBISFILE (gst_pad_get_parent (pad));
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_SEEK:
{
gint64 offset;
vorbis_info *vi;
if (!vorbisfile->vf.seekable) {
gst_event_unref (event);
return FALSE;
}
offset = GST_EVENT_SEEK_OFFSET (event);
switch (GST_EVENT_SEEK_FORMAT (event)) {
case GST_FORMAT_TIME:
vorbisfile->seek_pending = TRUE;
vorbisfile->seek_value = offset;
vorbisfile->seek_format = GST_FORMAT_TIME;
vorbisfile->seek_accurate = GST_EVENT_SEEK_FLAGS (event) & GST_SEEK_FLAG_ACCURATE;
break;
case GST_FORMAT_BYTES:
vi = ov_info (&vorbisfile->vf, -1);
if (vi->channels * 2 == 0) {
res = FALSE;
goto done;
}
offset /= vi->channels * 2;
/* fallthrough */
case GST_FORMAT_UNITS:
vorbisfile->seek_pending = TRUE;
vorbisfile->seek_value = offset;
vorbisfile->seek_format = GST_FORMAT_UNITS;
vorbisfile->seek_accurate = GST_EVENT_SEEK_FLAGS (event) & GST_SEEK_FLAG_ACCURATE;
break;
default:
res = FALSE;
break;
}
break;
}
default:
res = FALSE;
break;
}
done:
gst_event_unref (event);
return res;
}
static GstElementStateReturn
gst_vorbisfile_change_state (GstElement *element)
{
VorbisFile *vorbisfile = GST_VORBISFILE (element);
switch (GST_STATE_TRANSITION (element)) {
case GST_STATE_NULL_TO_READY:
case GST_STATE_READY_TO_PAUSED:
vorbisfile->restart = TRUE;
vorbisfile->bs = gst_bytestream_new (vorbisfile->sinkpad);
break;
case GST_STATE_PAUSED_TO_PLAYING:
vorbisfile->eos = FALSE;
case GST_STATE_PLAYING_TO_PAUSED:
break;
case GST_STATE_PAUSED_TO_READY:
ov_clear (&vorbisfile->vf);
gst_bytestream_destroy (vorbisfile->bs);
break;
case GST_STATE_READY_TO_NULL:
default:
break;
}
if (GST_ELEMENT_CLASS (parent_class)->change_state)
return GST_ELEMENT_CLASS (parent_class)->change_state (element);
return GST_STATE_SUCCESS;
}
static void
gst_vorbisfile_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
VorbisFile *vorbisfile;
g_return_if_fail (GST_IS_VORBISFILE (object));
vorbisfile = GST_VORBISFILE (object);
switch (prop_id) {
case ARG_COMMENT:
g_value_set_string (value, "comment");
break;
case ARG_VENDOR:
break;
case ARG_VERSION:
break;
case ARG_CHANNELS:
break;
case ARG_RATE:
break;
case ARG_BITRATE_UPPER:
break;
case ARG_BITRATE_NOMINAL:
break;
case ARG_BITRATE_LOWER:
break;
case ARG_BITRATE_WINDOW:
break;
}
}