gstreamer/gst/law/alaw-decode.c

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/* GStreamer
* Copyright (C) 1999 Erik Walthinsen <omega@cse.ogi.edu>
* PCM - A-Law conversion
* Copyright (C) 2000 by Abramo Bagnara <abramo@alsa-project.org>
*
* 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 2.1 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 <gst/gst.h>
#include "alaw-decode.h"
extern GstPadTemplate *alawdec_src_template, *alawdec_sink_template;
/* Stereo signals and args */
enum {
/* FILL ME */
LAST_SIGNAL
};
enum {
ARG_0
};
static void gst_alawdec_class_init (GstALawDecClass *klass);
static void gst_alawdec_init (GstALawDec *alawdec);
static void gst_alawdec_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec);
static void gst_alawdec_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec);
static void gst_alawdec_chain (GstPad *pad, GstBuffer *buf);
static GstElementClass *parent_class = NULL;
/*static guint gst_stereo_signals[LAST_SIGNAL] = { 0 }; */
/*
* alaw_to_s16() - Convert an A-law value to 16-bit linear PCM
*
*/
static gint alaw_to_s16(guint8 a_val)
{
gint t;
gint seg;
a_val ^= 0x55;
t = a_val & 0x7f;
if (t < 16)
t = (t << 4) + 8;
else {
seg = (t >> 4) & 0x07;
t = ((t & 0x0f) << 4) + 0x108;
t <<= seg -1;
}
return ((a_val & 0x80) ? t : -t);
}
static GstPadLinkReturn
alawdec_link (GstPad *pad, GstCaps *caps)
{
GstCaps* tempcaps;
gint rate, channels;
GstALawDec* alawdec = GST_ALAWDEC (GST_OBJECT_PARENT (pad));
if (!GST_CAPS_IS_FIXED (caps))
return GST_PAD_LINK_DELAYED;
if (!gst_caps_get (caps, "rate", &rate,
"channels", &channels,
NULL))
return GST_PAD_LINK_DELAYED;
tempcaps = GST_CAPS_NEW (
"alawdec_src_caps",
"audio/raw",
"format", GST_PROPS_STRING ("int"),
"law", GST_PROPS_INT (0),
"depth", GST_PROPS_INT (16),
"width", GST_PROPS_INT (16),
"signed", GST_PROPS_BOOLEAN (TRUE),
"endianness", GST_PROPS_INT (G_BYTE_ORDER),
"rate", GST_PROPS_INT (rate),
"channels", GST_PROPS_INT (channels),
NULL);
return gst_pad_try_set_caps (alawdec->srcpad, tempcaps);
}
GType
gst_alawdec_get_type(void) {
static GType alawdec_type = 0;
if (!alawdec_type) {
static const GTypeInfo alawdec_info = {
sizeof(GstALawDecClass), NULL,
NULL,
(GClassInitFunc)gst_alawdec_class_init,
NULL,
NULL,
sizeof(GstALawDec),
0,
(GInstanceInitFunc)gst_alawdec_init,
};
alawdec_type = g_type_register_static(GST_TYPE_ELEMENT, "GstALawDec", &alawdec_info, 0);
}
return alawdec_type;
}
static void
gst_alawdec_class_init (GstALawDecClass *klass)
{
GObjectClass *gobject_class;
GstElementClass *gstelement_class;
gobject_class = (GObjectClass*)klass;
gstelement_class = (GstElementClass*)klass;
parent_class = g_type_class_ref(GST_TYPE_ELEMENT);
gobject_class->set_property = gst_alawdec_set_property;
gobject_class->get_property = gst_alawdec_get_property;
}
static void
gst_alawdec_init (GstALawDec *alawdec)
{
alawdec->sinkpad = gst_pad_new_from_template(alawdec_sink_template,"sink");
alawdec->srcpad = gst_pad_new_from_template(alawdec_src_template,"src");
gst_pad_set_link_function(alawdec->sinkpad, alawdec_link);
gst_element_add_pad(GST_ELEMENT(alawdec),alawdec->sinkpad);
gst_pad_set_chain_function(alawdec->sinkpad,gst_alawdec_chain);
gst_element_add_pad(GST_ELEMENT(alawdec),alawdec->srcpad);
}
static void
gst_alawdec_chain (GstPad *pad,GstBuffer *buf)
{
GstALawDec *alawdec;
gint16 *linear_data;
guint8 *alaw_data;
GstBuffer* outbuf;
gint i;
g_return_if_fail(pad != NULL);
g_return_if_fail(GST_IS_PAD(pad));
g_return_if_fail(buf != NULL);
alawdec = GST_ALAWDEC(GST_OBJECT_PARENT (pad));
g_return_if_fail(alawdec != NULL);
g_return_if_fail(GST_IS_ALAWDEC(alawdec));
alaw_data = (guint8 *)GST_BUFFER_DATA(buf);
outbuf=gst_buffer_new();
GST_BUFFER_DATA(outbuf) = (gchar*)g_new(gint16,GST_BUFFER_SIZE(buf));
GST_BUFFER_SIZE(outbuf) = GST_BUFFER_SIZE(buf)*2;
linear_data = (gint16*)GST_BUFFER_DATA(outbuf);
for (i = 0; i < GST_BUFFER_SIZE(buf); i++) {
*linear_data = alaw_to_s16 (*alaw_data);
linear_data++;
alaw_data++;
}
gst_buffer_unref(buf);
gst_pad_push(alawdec->srcpad,outbuf);
}
static void
gst_alawdec_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec)
{
GstALawDec *alawdec;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail(GST_IS_ALAWDEC(object));
alawdec = GST_ALAWDEC(object);
switch (prop_id) {
default:
break;
}
}
static void
gst_alawdec_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec)
{
GstALawDec *alawdec;
/* it's not null if we got it, but it might not be ours */
g_return_if_fail(GST_IS_ALAWDEC(object));
alawdec = GST_ALAWDEC(object);
switch (prop_id) {
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}