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1 /* GStreamer
2  * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
3  * Copyright (C) <2005> Zeeshan Ali <zeenix@gmail.com>
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Library General Public
7  * License as published by the Free Software Foundation; either
8  * version 2 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * Library General Public License for more details.
14  *
15  * You should have received a copy of the GNU Library General Public
16  * License along with this library; if not, write to the
17  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
18  * Boston, MA 02110-1301, USA.
19  */
20 
21 #ifdef HAVE_CONFIG_H
22 #  include "config.h"
23 #endif
24 
25 #include <string.h>
26 #include <gst/rtp/gstrtpbuffer.h>
27 #include <gst/audio/audio.h>
28 #include "gstrtpelements.h"
29 #include "gstrtpgsmdepay.h"
30 #include "gstrtputils.h"
31 
32 GST_DEBUG_CATEGORY_STATIC (rtpgsmdepay_debug);
33 #define GST_CAT_DEFAULT (rtpgsmdepay_debug)
34 
35 /* RTPGSMDepay signals and args */
36 enum
37 {
38   /* FILL ME */
39   LAST_SIGNAL
40 };
41 
42 static GstStaticPadTemplate gst_rtp_gsm_depay_src_template =
43 GST_STATIC_PAD_TEMPLATE ("src",
44     GST_PAD_SRC,
45     GST_PAD_ALWAYS,
46     GST_STATIC_CAPS ("audio/x-gsm, " "rate = (int) 8000, " "channels = 1")
47     );
48 
49 static GstStaticPadTemplate gst_rtp_gsm_depay_sink_template =
50     GST_STATIC_PAD_TEMPLATE ("sink",
51     GST_PAD_SINK,
52     GST_PAD_ALWAYS,
53     GST_STATIC_CAPS ("application/x-rtp, "
54         "media = (string) \"audio\", "
55         "clock-rate = (int) 8000, " "encoding-name = (string) \"GSM\";"
56         "application/x-rtp, "
57         "media = (string) \"audio\", "
58         "payload = (int) " GST_RTP_PAYLOAD_GSM_STRING ", "
59         "clock-rate = (int) 8000")
60     );
61 
62 static GstBuffer *gst_rtp_gsm_depay_process (GstRTPBaseDepayload * _depayload,
63     GstRTPBuffer * rtp);
64 static gboolean gst_rtp_gsm_depay_setcaps (GstRTPBaseDepayload * _depayload,
65     GstCaps * caps);
66 
67 #define gst_rtp_gsm_depay_parent_class parent_class
68 G_DEFINE_TYPE (GstRTPGSMDepay, gst_rtp_gsm_depay, GST_TYPE_RTP_BASE_DEPAYLOAD);
69 GST_ELEMENT_REGISTER_DEFINE_WITH_CODE (rtpgsmdepay, "rtpgsmdepay",
70     GST_RANK_SECONDARY, GST_TYPE_RTP_GSM_DEPAY, rtp_element_init (plugin));
71 
72 static void
gst_rtp_gsm_depay_class_init(GstRTPGSMDepayClass * klass)73 gst_rtp_gsm_depay_class_init (GstRTPGSMDepayClass * klass)
74 {
75   GstElementClass *gstelement_class;
76   GstRTPBaseDepayloadClass *gstrtpbase_depayload_class;
77 
78   gstelement_class = (GstElementClass *) klass;
79   gstrtpbase_depayload_class = (GstRTPBaseDepayloadClass *) klass;
80 
81   gst_element_class_add_static_pad_template (gstelement_class,
82       &gst_rtp_gsm_depay_src_template);
83   gst_element_class_add_static_pad_template (gstelement_class,
84       &gst_rtp_gsm_depay_sink_template);
85 
86   gst_element_class_set_static_metadata (gstelement_class,
87       "RTP GSM depayloader", "Codec/Depayloader/Network/RTP",
88       "Extracts GSM audio from RTP packets", "Zeeshan Ali <zeenix@gmail.com>");
89 
90   gstrtpbase_depayload_class->process_rtp_packet = gst_rtp_gsm_depay_process;
91   gstrtpbase_depayload_class->set_caps = gst_rtp_gsm_depay_setcaps;
92 
93   GST_DEBUG_CATEGORY_INIT (rtpgsmdepay_debug, "rtpgsmdepay", 0,
94       "GSM Audio RTP Depayloader");
95 }
96 
97 static void
gst_rtp_gsm_depay_init(GstRTPGSMDepay * rtpgsmdepay)98 gst_rtp_gsm_depay_init (GstRTPGSMDepay * rtpgsmdepay)
99 {
100 }
101 
102 static gboolean
gst_rtp_gsm_depay_setcaps(GstRTPBaseDepayload * depayload,GstCaps * caps)103 gst_rtp_gsm_depay_setcaps (GstRTPBaseDepayload * depayload, GstCaps * caps)
104 {
105   GstCaps *srccaps;
106   gboolean ret;
107   GstStructure *structure;
108   gint clock_rate;
109 
110   structure = gst_caps_get_structure (caps, 0);
111 
112   if (!gst_structure_get_int (structure, "clock-rate", &clock_rate))
113     clock_rate = 8000;          /* default */
114   depayload->clock_rate = clock_rate;
115 
116   srccaps = gst_caps_new_simple ("audio/x-gsm",
117       "channels", G_TYPE_INT, 1, "rate", G_TYPE_INT, clock_rate, NULL);
118   ret = gst_pad_set_caps (GST_RTP_BASE_DEPAYLOAD_SRCPAD (depayload), srccaps);
119   gst_caps_unref (srccaps);
120 
121   return ret;
122 }
123 
124 static GstBuffer *
gst_rtp_gsm_depay_process(GstRTPBaseDepayload * depayload,GstRTPBuffer * rtp)125 gst_rtp_gsm_depay_process (GstRTPBaseDepayload * depayload, GstRTPBuffer * rtp)
126 {
127   GstBuffer *outbuf = NULL;
128   gboolean marker;
129 
130   marker = gst_rtp_buffer_get_marker (rtp);
131 
132   GST_DEBUG ("process : got %" G_GSIZE_FORMAT " bytes, mark %d ts %u seqn %d",
133       gst_buffer_get_size (rtp->buffer), marker,
134       gst_rtp_buffer_get_timestamp (rtp), gst_rtp_buffer_get_seq (rtp));
135 
136   outbuf = gst_rtp_buffer_get_payload_buffer (rtp);
137 
138   if (marker && outbuf) {
139     /* mark start of talkspurt with RESYNC */
140     GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_RESYNC);
141   }
142 
143   if (outbuf) {
144     gst_rtp_drop_non_audio_meta (depayload, outbuf);
145   }
146 
147   return outbuf;
148 }
149