1 /* GStreamer
2 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 */
19 /**
20 * SECTION:element-mulawdec
21 *
22 * This element decodes mulaw audio. Mulaw coding is also known as G.711.
23 */
24
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28 #include <gst/gst.h>
29
30 #include "mulaw-decode.h"
31 #include "mulaw-conversion.h"
32
33 extern GstStaticPadTemplate mulaw_dec_src_factory;
34 extern GstStaticPadTemplate mulaw_dec_sink_factory;
35
36 static gboolean gst_mulawdec_set_format (GstAudioDecoder * dec, GstCaps * caps);
37 static GstFlowReturn gst_mulawdec_handle_frame (GstAudioDecoder * dec,
38 GstBuffer * buffer);
39
40
41 /* Stereo signals and args */
42 enum
43 {
44 /* FILL ME */
45 LAST_SIGNAL
46 };
47
48 enum
49 {
50 PROP_0
51 };
52
53 #define gst_mulawdec_parent_class parent_class
54 G_DEFINE_TYPE (GstMuLawDec, gst_mulawdec, GST_TYPE_AUDIO_DECODER);
55
56 static gboolean
gst_mulawdec_set_format(GstAudioDecoder * dec,GstCaps * caps)57 gst_mulawdec_set_format (GstAudioDecoder * dec, GstCaps * caps)
58 {
59 GstMuLawDec *mulawdec = GST_MULAWDEC (dec);
60 GstStructure *structure;
61 int rate, channels;
62 GstAudioInfo info;
63
64 structure = gst_caps_get_structure (caps, 0);
65 if (!structure) {
66 GST_ERROR ("failed to get structure from caps");
67 goto error_failed_get_structure;
68 }
69
70 if (!gst_structure_get_int (structure, "rate", &rate)) {
71 GST_ERROR ("failed to find field rate in input caps");
72 goto error_failed_find_rate;
73 }
74
75 if (!gst_structure_get_int (structure, "channels", &channels)) {
76 GST_ERROR ("failed to find field channels in input caps");
77 goto error_failed_find_channel;
78 }
79
80 gst_audio_info_init (&info);
81 gst_audio_info_set_format (&info, GST_AUDIO_FORMAT_S16, rate, channels, NULL);
82
83 GST_DEBUG_OBJECT (mulawdec, "rate=%d, channels=%d", rate, channels);
84
85 return gst_audio_decoder_set_output_format (dec, &info);
86
87 error_failed_find_channel:
88 error_failed_find_rate:
89 error_failed_get_structure:
90 return FALSE;
91 }
92
93 static GstFlowReturn
gst_mulawdec_handle_frame(GstAudioDecoder * dec,GstBuffer * buffer)94 gst_mulawdec_handle_frame (GstAudioDecoder * dec, GstBuffer * buffer)
95 {
96 GstMapInfo inmap, outmap;
97 gint16 *linear_data;
98 guint8 *mulaw_data;
99 gsize mulaw_size, linear_size;
100 GstBuffer *outbuf;
101
102 if (!buffer) {
103 return GST_FLOW_OK;
104 }
105
106 if (!gst_buffer_map (buffer, &inmap, GST_MAP_READ)) {
107 GST_ERROR ("failed to map input buffer");
108 goto error_failed_map_input_buffer;
109 }
110
111 mulaw_data = inmap.data;
112 mulaw_size = inmap.size;
113
114 linear_size = mulaw_size * 2;
115
116 outbuf = gst_audio_decoder_allocate_output_buffer (dec, linear_size);
117 if (!gst_buffer_map (outbuf, &outmap, GST_MAP_WRITE)) {
118 GST_ERROR ("failed to map input buffer");
119 goto error_failed_map_output_buffer;
120 }
121
122 linear_data = (gint16 *) outmap.data;
123
124 mulaw_decode (mulaw_data, linear_data, mulaw_size);
125
126 gst_buffer_unmap (outbuf, &outmap);
127 gst_buffer_unmap (buffer, &inmap);
128
129 return gst_audio_decoder_finish_frame (dec, outbuf, -1);
130
131 error_failed_map_output_buffer:
132 gst_buffer_unref (outbuf);
133 gst_buffer_unmap (buffer, &inmap);
134
135 error_failed_map_input_buffer:
136 return GST_FLOW_ERROR;
137 }
138
139 static gboolean
gst_mulawdec_start(GstAudioDecoder * dec)140 gst_mulawdec_start (GstAudioDecoder * dec)
141 {
142 gst_audio_decoder_set_estimate_rate (dec, TRUE);
143
144 return TRUE;
145 }
146
147 static void
gst_mulawdec_class_init(GstMuLawDecClass * klass)148 gst_mulawdec_class_init (GstMuLawDecClass * klass)
149 {
150 GstElementClass *element_class = (GstElementClass *) klass;
151 GstAudioDecoderClass *audiodec_class = GST_AUDIO_DECODER_CLASS (klass);
152
153 gst_element_class_add_static_pad_template (element_class,
154 &mulaw_dec_src_factory);
155 gst_element_class_add_static_pad_template (element_class,
156 &mulaw_dec_sink_factory);
157
158
159 audiodec_class->start = GST_DEBUG_FUNCPTR (gst_mulawdec_start);
160 audiodec_class->set_format = GST_DEBUG_FUNCPTR (gst_mulawdec_set_format);
161 audiodec_class->handle_frame = GST_DEBUG_FUNCPTR (gst_mulawdec_handle_frame);
162
163 gst_element_class_set_static_metadata (element_class, "Mu Law audio decoder",
164 "Codec/Decoder/Audio",
165 "Convert 8bit mu law to 16bit PCM",
166 "Zaheer Abbas Merali <zaheerabbas at merali dot org>");
167 }
168
169 static void
gst_mulawdec_init(GstMuLawDec * mulawdec)170 gst_mulawdec_init (GstMuLawDec * mulawdec)
171 {
172 gst_audio_decoder_set_needs_format (GST_AUDIO_DECODER (mulawdec), TRUE);
173 gst_audio_decoder_set_use_default_pad_acceptcaps (GST_AUDIO_DECODER_CAST
174 (mulawdec), TRUE);
175 GST_PAD_SET_ACCEPT_TEMPLATE (GST_AUDIO_DECODER_SINK_PAD (mulawdec));
176 }
177