gstreamer/gst/law/mulaw-encode.c
2012-04-10 00:51:41 +01:00

303 lines
8 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.
*/
/**
* SECTION:element-mulawenc
*
* This element encode mulaw audio. Mulaw coding is also known as G.711.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <gst/gst.h>
#include <gst/audio/audio.h>
#include "mulaw-encode.h"
#include "mulaw-conversion.h"
extern GstStaticPadTemplate mulaw_enc_src_factory;
extern GstStaticPadTemplate mulaw_enc_sink_factory;
/* Stereo signals and args */
enum
{
/* FILL ME */
LAST_SIGNAL
};
enum
{
ARG_0
};
static gboolean gst_mulawenc_event (GstPad * pad, GstObject * parent,
GstEvent * event);
static GstFlowReturn gst_mulawenc_chain (GstPad * pad, GstObject * parent,
GstBuffer * buffer);
#define gst_mulawenc_parent_class parent_class
G_DEFINE_TYPE (GstMuLawEnc, gst_mulawenc, GST_TYPE_ELEMENT);
/*static guint gst_stereo_signals[LAST_SIGNAL] = { 0 }; */
static GstCaps *
mulawenc_getcaps (GstPad * pad, GstCaps * filter)
{
GstMuLawEnc *mulawenc;
GstPad *otherpad;
GstCaps *othercaps, *result;
GstCaps *templ;
const gchar *name;
gint i;
mulawenc = GST_MULAWENC (GST_PAD_PARENT (pad));
/* figure out the name of the caps we are going to return */
if (pad == mulawenc->srcpad) {
name = "audio/x-mulaw";
otherpad = mulawenc->sinkpad;
} else {
name = "audio/x-raw";
otherpad = mulawenc->srcpad;
}
/* get caps from the peer, this can return NULL when there is no peer */
othercaps = gst_pad_peer_query_caps (otherpad, NULL);
/* get the template caps to make sure we return something acceptable */
templ = gst_pad_get_pad_template_caps (pad);
if (othercaps) {
/* there was a peer */
othercaps = gst_caps_make_writable (othercaps);
/* go through the caps and remove the fields we don't want */
for (i = 0; i < gst_caps_get_size (othercaps); i++) {
GstStructure *structure;
structure = gst_caps_get_structure (othercaps, i);
/* adjust the name */
gst_structure_set_name (structure, name);
if (pad == mulawenc->srcpad) {
/* remove the fields we don't want */
gst_structure_remove_fields (structure, "format", NULL);
} else {
/* add fixed fields */
gst_structure_set (structure, "format", G_TYPE_STRING,
GST_AUDIO_NE (S16), NULL);
}
}
/* filter against the allowed caps of the pad to return our result */
result = gst_caps_intersect (othercaps, templ);
gst_caps_unref (othercaps);
gst_caps_unref (templ);
} else {
/* there was no peer, return the template caps */
result = templ;
}
if (filter && result) {
GstCaps *temp;
temp = gst_caps_intersect (result, filter);
gst_caps_unref (result);
result = temp;
}
return result;
}
static gboolean
gst_mulawenc_query (GstPad * pad, GstObject * parent, GstQuery * query)
{
gboolean res;
switch (GST_QUERY_TYPE (query)) {
case GST_QUERY_CAPS:
{
GstCaps *filter, *caps;
gst_query_parse_caps (query, &filter);
caps = mulawenc_getcaps (pad, filter);
gst_query_set_caps_result (query, caps);
gst_caps_unref (caps);
res = TRUE;
break;
}
default:
res = gst_pad_query_default (pad, parent, query);
break;
}
return res;
}
static gboolean
mulawenc_setcaps (GstMuLawEnc * mulawenc, GstCaps * caps)
{
GstStructure *structure;
GstCaps *base_caps;
structure = gst_caps_get_structure (caps, 0);
gst_structure_get_int (structure, "channels", &mulawenc->channels);
gst_structure_get_int (structure, "rate", &mulawenc->rate);
base_caps = gst_pad_get_pad_template_caps (mulawenc->srcpad);
base_caps = gst_caps_make_writable (base_caps);
structure = gst_caps_get_structure (base_caps, 0);
gst_structure_set (structure, "rate", G_TYPE_INT, mulawenc->rate, NULL);
gst_structure_set (structure, "channels", G_TYPE_INT, mulawenc->channels,
NULL);
gst_pad_set_caps (mulawenc->srcpad, base_caps);
gst_caps_unref (base_caps);
return TRUE;
}
static void
gst_mulawenc_class_init (GstMuLawEncClass * klass)
{
GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&mulaw_enc_src_factory));
gst_element_class_add_pad_template (element_class,
gst_static_pad_template_get (&mulaw_enc_sink_factory));
gst_element_class_set_static_metadata (element_class, "Mu Law audio encoder",
"Codec/Encoder/Audio",
"Convert 16bit PCM to 8bit mu law",
"Zaheer Abbas Merali <zaheerabbas at merali dot org>");
}
static void
gst_mulawenc_init (GstMuLawEnc * mulawenc)
{
mulawenc->sinkpad =
gst_pad_new_from_static_template (&mulaw_enc_sink_factory, "sink");
gst_pad_set_query_function (mulawenc->sinkpad, gst_mulawenc_query);
gst_pad_set_event_function (mulawenc->sinkpad, gst_mulawenc_event);
gst_pad_set_chain_function (mulawenc->sinkpad, gst_mulawenc_chain);
gst_element_add_pad (GST_ELEMENT (mulawenc), mulawenc->sinkpad);
mulawenc->srcpad =
gst_pad_new_from_static_template (&mulaw_enc_src_factory, "src");
gst_pad_set_query_function (mulawenc->srcpad, gst_mulawenc_query);
gst_element_add_pad (GST_ELEMENT (mulawenc), mulawenc->srcpad);
/* init rest */
mulawenc->channels = 0;
mulawenc->rate = 0;
}
static gboolean
gst_mulawenc_event (GstPad * pad, GstObject * parent, GstEvent * event)
{
GstMuLawEnc *mulawenc;
gboolean res;
mulawenc = GST_MULAWENC (parent);
switch (GST_EVENT_TYPE (event)) {
case GST_EVENT_CAPS:
{
GstCaps *caps;
gst_event_parse_caps (event, &caps);
mulawenc_setcaps (mulawenc, caps);
gst_event_unref (event);
res = TRUE;
break;
}
default:
res = gst_pad_event_default (pad, parent, event);
break;
}
return res;
}
static GstFlowReturn
gst_mulawenc_chain (GstPad * pad, GstObject * parent, GstBuffer * buffer)
{
GstMuLawEnc *mulawenc;
GstMapInfo inmap, outmap;
gint16 *linear_data;
gsize linear_size;
guint8 *mulaw_data;
guint mulaw_size;
GstBuffer *outbuf;
GstFlowReturn ret;
GstClockTime timestamp, duration;
mulawenc = GST_MULAWENC (parent);
if (!mulawenc->rate || !mulawenc->channels)
goto not_negotiated;
gst_buffer_map (buffer, &inmap, GST_MAP_READ);
linear_data = (gint16 *) inmap.data;
linear_size = inmap.size;
mulaw_size = linear_size / 2;
timestamp = GST_BUFFER_TIMESTAMP (buffer);
duration = GST_BUFFER_DURATION (buffer);
outbuf = gst_buffer_new_allocate (NULL, mulaw_size, NULL);
if (duration == -1) {
duration = gst_util_uint64_scale_int (mulaw_size,
GST_SECOND, mulawenc->rate * mulawenc->channels);
}
gst_buffer_map (outbuf, &outmap, GST_MAP_WRITE);
mulaw_data = outmap.data;
/* copy discont flag */
if (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DISCONT))
GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DISCONT);
GST_BUFFER_TIMESTAMP (outbuf) = timestamp;
GST_BUFFER_DURATION (outbuf) = duration;
mulaw_encode (linear_data, mulaw_data, mulaw_size);
gst_buffer_unmap (outbuf, &outmap);
gst_buffer_unmap (buffer, &inmap);
gst_buffer_unref (buffer);
ret = gst_pad_push (mulawenc->srcpad, outbuf);
done:
return ret;
not_negotiated:
{
GST_DEBUG_OBJECT (mulawenc, "no format negotiated");
ret = GST_FLOW_NOT_NEGOTIATED;
gst_buffer_unref (buffer);
goto done;
}
}