1 /* GStreamer A-Law to PCM conversion
2 * Copyright (C) 2000 by Abramo Bagnara <abramo@alsa-project.org>
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 2.1 of the License, or (at your option) any later version.
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.
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., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
20 * SECTION:element-alawdec
22 * This element decodes alaw audio. Alaw coding is also known as G.711.
29 #include "alaw-decode.h"
31 extern GstStaticPadTemplate alaw_dec_src_factory;
32 extern GstStaticPadTemplate alaw_dec_sink_factory;
34 GST_DEBUG_CATEGORY_STATIC (alaw_dec_debug);
35 #define GST_CAT_DEFAULT alaw_dec_debug
37 static GstStateChangeReturn
38 gst_alaw_dec_change_state (GstElement * element, GstStateChange transition);
40 static gboolean gst_alaw_dec_event (GstPad * pad, GstEvent * event);
41 static GstFlowReturn gst_alaw_dec_chain (GstPad * pad, GstBuffer * buffer);
43 #define gst_alaw_dec_parent_class parent_class
44 G_DEFINE_TYPE (GstALawDec, gst_alaw_dec, GST_TYPE_ELEMENT);
46 /* some day we might have defines in gstconfig.h that tell us about the
47 * desired cpu/memory/binary size trade-offs */
48 #define GST_ALAW_DEC_USE_TABLE
50 #ifdef GST_ALAW_DEC_USE_TABLE
52 static const gint alaw_to_s16_table[256] = {
53 -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736,
54 -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784,
55 -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368,
56 -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392,
57 -22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944,
58 -30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136,
59 -11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472,
60 -15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568,
61 -344, -328, -376, -360, -280, -264, -312, -296,
62 -472, -456, -504, -488, -408, -392, -440, -424,
63 -88, -72, -120, -104, -24, -8, -56, -40,
64 -216, -200, -248, -232, -152, -136, -184, -168,
65 -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184,
66 -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696,
67 -688, -656, -752, -720, -560, -528, -624, -592,
68 -944, -912, -1008, -976, -816, -784, -880, -848,
69 5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736,
70 7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784,
71 2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368,
72 3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392,
73 22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944,
74 30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136,
75 11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472,
76 15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568,
77 344, 328, 376, 360, 280, 264, 312, 296,
78 472, 456, 504, 488, 408, 392, 440, 424,
79 88, 72, 120, 104, 24, 8, 56, 40,
80 216, 200, 248, 232, 152, 136, 184, 168,
81 1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184,
82 1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696,
83 688, 656, 752, 720, 560, 528, 624, 592,
84 944, 912, 1008, 976, 816, 784, 880, 848
88 alaw_to_s16 (guint8 a_val)
90 return alaw_to_s16_table[a_val];
93 #else /* GST_ALAW_DEC_USE_TABLE */
96 alaw_to_s16 (guint8 a_val)
106 seg = (t >> 4) & 0x07;
107 t = ((t & 0x0f) << 4) + 0x108;
110 return ((a_val & 0x80) ? t : -t);
113 #endif /* GST_ALAW_DEC_USE_TABLE */
116 gst_alaw_dec_setcaps (GstALawDec * alawdec, GstCaps * caps)
118 GstStructure *structure;
123 structure = gst_caps_get_structure (caps, 0);
125 ret = gst_structure_get_int (structure, "rate", &rate);
126 ret &= gst_structure_get_int (structure, "channels", &channels);
130 outcaps = gst_caps_new_simple ("audio/x-raw-int",
131 "width", G_TYPE_INT, 16,
132 "depth", G_TYPE_INT, 16,
133 "endianness", G_TYPE_INT, G_BYTE_ORDER,
134 "signed", G_TYPE_BOOLEAN, TRUE,
135 "rate", G_TYPE_INT, rate, "channels", G_TYPE_INT, channels, NULL);
137 ret = gst_pad_set_caps (alawdec->srcpad, outcaps);
138 gst_caps_unref (outcaps);
141 GST_DEBUG_OBJECT (alawdec, "rate=%d, channels=%d", rate, channels);
142 alawdec->rate = rate;
143 alawdec->channels = channels;
149 gst_alaw_dec_getcaps (GstPad * pad, GstCaps * filter)
153 GstCaps *othercaps, *result;
154 const GstCaps *templ;
158 alawdec = GST_ALAW_DEC (GST_PAD_PARENT (pad));
160 /* figure out the name of the caps we are going to return */
161 if (pad == alawdec->srcpad) {
162 name = "audio/x-raw-int";
163 otherpad = alawdec->sinkpad;
165 name = "audio/x-alaw";
166 otherpad = alawdec->srcpad;
168 /* get caps from the peer, this can return NULL when there is no peer */
169 othercaps = gst_pad_peer_get_caps (otherpad, filter);
171 /* get the template caps to make sure we return something acceptable */
172 templ = gst_pad_get_pad_template_caps (pad);
175 /* there was a peer */
176 othercaps = gst_caps_make_writable (othercaps);
178 /* go through the caps and remove the fields we don't want */
179 for (i = 0; i < gst_caps_get_size (othercaps); i++) {
180 GstStructure *structure;
182 structure = gst_caps_get_structure (othercaps, i);
184 /* adjust the name */
185 gst_structure_set_name (structure, name);
187 if (pad == alawdec->sinkpad) {
188 /* remove the fields we don't want */
189 gst_structure_remove_fields (structure, "width", "depth", "endianness",
192 /* add fixed fields */
193 gst_structure_set (structure, "width", G_TYPE_INT, 16,
194 "depth", G_TYPE_INT, 16,
195 "endianness", G_TYPE_INT, G_BYTE_ORDER,
196 "signed", G_TYPE_BOOLEAN, TRUE, NULL);
199 /* filter against the allowed caps of the pad to return our result */
200 result = gst_caps_intersect (othercaps, templ);
201 gst_caps_unref (othercaps);
203 /* there was no peer, return the template caps */
204 result = gst_caps_copy (templ);
211 gst_alaw_dec_class_init (GstALawDecClass * klass)
213 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
215 gst_element_class_add_pad_template (element_class,
216 gst_static_pad_template_get (&alaw_dec_src_factory));
217 gst_element_class_add_pad_template (element_class,
218 gst_static_pad_template_get (&alaw_dec_sink_factory));
220 gst_element_class_set_details_simple (element_class, "A Law audio decoder",
221 "Codec/Decoder/Audio", "Convert 8bit A law to 16bit PCM",
222 "Zaheer Abbas Merali <zaheerabbas at merali dot org>");
224 element_class->change_state = GST_DEBUG_FUNCPTR (gst_alaw_dec_change_state);
226 GST_DEBUG_CATEGORY_INIT (alaw_dec_debug, "alawdec", 0, "A Law audio decoder");
230 gst_alaw_dec_init (GstALawDec * alawdec)
233 gst_pad_new_from_static_template (&alaw_dec_sink_factory, "sink");
234 gst_pad_set_getcaps_function (alawdec->sinkpad,
235 GST_DEBUG_FUNCPTR (gst_alaw_dec_getcaps));
236 gst_pad_set_event_function (alawdec->sinkpad,
237 GST_DEBUG_FUNCPTR (gst_alaw_dec_event));
238 gst_pad_set_chain_function (alawdec->sinkpad,
239 GST_DEBUG_FUNCPTR (gst_alaw_dec_chain));
240 gst_element_add_pad (GST_ELEMENT (alawdec), alawdec->sinkpad);
243 gst_pad_new_from_static_template (&alaw_dec_src_factory, "src");
244 gst_pad_use_fixed_caps (alawdec->srcpad);
245 gst_pad_set_getcaps_function (alawdec->srcpad,
246 GST_DEBUG_FUNCPTR (gst_alaw_dec_getcaps));
247 gst_element_add_pad (GST_ELEMENT (alawdec), alawdec->srcpad);
251 gst_alaw_dec_event (GstPad * pad, GstEvent * event)
256 alawdec = GST_ALAW_DEC (GST_PAD_PARENT (pad));
258 switch (GST_EVENT_TYPE (event)) {
263 gst_event_parse_caps (event, &caps);
264 gst_alaw_dec_setcaps (alawdec, caps);
265 gst_event_unref (event);
271 res = gst_pad_event_default (pad, event);
278 gst_alaw_dec_chain (GstPad * pad, GstBuffer * buffer)
288 alawdec = GST_ALAW_DEC (GST_PAD_PARENT (pad));
290 if (G_UNLIKELY (alawdec->rate == 0))
293 GST_LOG_OBJECT (alawdec, "buffer with ts=%" GST_TIME_FORMAT,
294 GST_TIME_ARGS (GST_BUFFER_TIMESTAMP (buffer)));
296 alaw_data = gst_buffer_map (buffer, &alaw_size, NULL, GST_MAP_READ);
298 outbuf = gst_buffer_new_allocate (NULL, alaw_size, 0);
300 linear_data = gst_buffer_map (outbuf, NULL, NULL, GST_MAP_WRITE);
302 /* copy discont flag */
303 if (GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_FLAG_DISCONT))
304 GST_BUFFER_FLAG_SET (outbuf, GST_BUFFER_FLAG_DISCONT);
306 GST_BUFFER_TIMESTAMP (outbuf) = GST_BUFFER_TIMESTAMP (buffer);
307 GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (buffer);
309 for (i = 0; i < alaw_size; i++) {
310 linear_data[i] = alaw_to_s16 (alaw_data[i]);
313 gst_buffer_unmap (outbuf, linear_data, -1);
314 gst_buffer_unmap (buffer, alaw_data, -1);
315 gst_buffer_unref (buffer);
317 ret = gst_pad_push (alawdec->srcpad, outbuf);
323 gst_buffer_unref (buffer);
324 GST_WARNING_OBJECT (alawdec, "no input format set: not-negotiated");
325 return GST_FLOW_NOT_NEGOTIATED;
329 static GstStateChangeReturn
330 gst_alaw_dec_change_state (GstElement * element, GstStateChange transition)
332 GstStateChangeReturn ret;
333 GstALawDec *dec = GST_ALAW_DEC (element);
335 switch (transition) {
340 ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
341 if (ret != GST_STATE_CHANGE_SUCCESS)
344 switch (transition) {
345 case GST_STATE_CHANGE_PAUSED_TO_READY: