GStreamer (Good Plugins): gst/law/alaw-decode.c

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Member "gst-plugins-good-1.20.3/gst/law/alaw-decode.c" (15 Jun 2022, 7944 Bytes) of package /linux/misc/gst-plugins-good-1.20.3.tar.xz:

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1 /* GStreamer A-Law to PCM conversion 2 * Copyright (C) 2000 by Abramo Bagnara <abramo@alsa-project.org> 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 2.1 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-alawdec 21 * @title: alawdec 22 * 23 * This element decodes alaw audio. Alaw coding is also known as G.711. 24 */ 25 26 #ifdef HAVE_CONFIG_H 27 #include "config.h" 28 #endif 29 30 #include "alaw-decode.h" 31 32 extern GstStaticPadTemplate alaw_dec_src_factory; 33 extern GstStaticPadTemplate alaw_dec_sink_factory; 34 35 GST_DEBUG_CATEGORY_STATIC (alaw_dec_debug); 36 #define GST_CAT_DEFAULT alaw_dec_debug 37 38 static gboolean gst_alaw_dec_set_format (GstAudioDecoder * dec, GstCaps * caps); 39 static GstFlowReturn gst_alaw_dec_handle_frame (GstAudioDecoder * dec, 40 GstBuffer * buffer); 41 42 #define gst_alaw_dec_parent_class parent_class 43 G_DEFINE_TYPE (GstALawDec, gst_alaw_dec, GST_TYPE_AUDIO_DECODER); 44 GST_ELEMENT_REGISTER_DEFINE (alawdec, "alawdec", GST_RANK_PRIMARY, 45 GST_TYPE_ALAW_DEC); 46 47 /* some day we might have defines in gstconfig.h that tell us about the 48 * desired cpu/memory/binary size trade-offs */ 49 #define GST_ALAW_DEC_USE_TABLE 50 51 #ifdef GST_ALAW_DEC_USE_TABLE 52 53 static const gint alaw_to_s16_table[256] = { 54 -5504, -5248, -6016, -5760, -4480, -4224, -4992, -4736, 55 -7552, -7296, -8064, -7808, -6528, -6272, -7040, -6784, 56 -2752, -2624, -3008, -2880, -2240, -2112, -2496, -2368, 57 -3776, -3648, -4032, -3904, -3264, -3136, -3520, -3392, 58 -22016, -20992, -24064, -23040, -17920, -16896, -19968, -18944, 59 -30208, -29184, -32256, -31232, -26112, -25088, -28160, -27136, 60 -11008, -10496, -12032, -11520, -8960, -8448, -9984, -9472, 61 -15104, -14592, -16128, -15616, -13056, -12544, -14080, -13568, 62 -344, -328, -376, -360, -280, -264, -312, -296, 63 -472, -456, -504, -488, -408, -392, -440, -424, 64 -88, -72, -120, -104, -24, -8, -56, -40, 65 -216, -200, -248, -232, -152, -136, -184, -168, 66 -1376, -1312, -1504, -1440, -1120, -1056, -1248, -1184, 67 -1888, -1824, -2016, -1952, -1632, -1568, -1760, -1696, 68 -688, -656, -752, -720, -560, -528, -624, -592, 69 -944, -912, -1008, -976, -816, -784, -880, -848, 70 5504, 5248, 6016, 5760, 4480, 4224, 4992, 4736, 71 7552, 7296, 8064, 7808, 6528, 6272, 7040, 6784, 72 2752, 2624, 3008, 2880, 2240, 2112, 2496, 2368, 73 3776, 3648, 4032, 3904, 3264, 3136, 3520, 3392, 74 22016, 20992, 24064, 23040, 17920, 16896, 19968, 18944, 75 30208, 29184, 32256, 31232, 26112, 25088, 28160, 27136, 76 11008, 10496, 12032, 11520, 8960, 8448, 9984, 9472, 77 15104, 14592, 16128, 15616, 13056, 12544, 14080, 13568, 78 344, 328, 376, 360, 280, 264, 312, 296, 79 472, 456, 504, 488, 408, 392, 440, 424, 80 88, 72, 120, 104, 24, 8, 56, 40, 81 216, 200, 248, 232, 152, 136, 184, 168, 82 1376, 1312, 1504, 1440, 1120, 1056, 1248, 1184, 83 1888, 1824, 2016, 1952, 1632, 1568, 1760, 1696, 84 688, 656, 752, 720, 560, 528, 624, 592, 85 944, 912, 1008, 976, 816, 784, 880, 848 86 }; 87 88 static inline gint 89 alaw_to_s16 (guint8 a_val) 90 { 91 return alaw_to_s16_table[a_val]; 92 } 93 94 #else /* GST_ALAW_DEC_USE_TABLE */ 95 96 static inline gint 97 alaw_to_s16 (guint8 a_val) 98 { 99 gint t; 100 gint seg; 101 102 a_val ^= 0x55; 103 t = a_val & 0x7f; 104 if (t < 16) 105 t = (t << 4) + 8; 106 else { 107 seg = (t >> 4) & 0x07; 108 t = ((t & 0x0f) << 4) + 0x108; 109 t <<= seg - 1; 110 } 111 return ((a_val & 0x80) ? t : -t); 112 } 113 114 #endif /* GST_ALAW_DEC_USE_TABLE */ 115 116 GstStaticPadTemplate alaw_dec_src_factory = GST_STATIC_PAD_TEMPLATE ("src", 117 GST_PAD_SRC, 118 GST_PAD_ALWAYS, 119 GST_STATIC_CAPS ("audio/x-raw, " 120 "format = (string) " GST_AUDIO_NE (S16) ", " 121 "layout = (string) interleaved, " 122 "rate = (int) [ 8000, 192000 ], " "channels = (int) [ 1, 2 ]") 123 ); 124 125 GstStaticPadTemplate alaw_dec_sink_factory = GST_STATIC_PAD_TEMPLATE ("sink", 126 GST_PAD_SINK, 127 GST_PAD_ALWAYS, 128 GST_STATIC_CAPS ("audio/x-alaw, " 129 "rate = [ 8000 , 192000 ], " "channels = [ 1 , 2 ]") 130 ); 131 132 static gboolean 133 gst_alaw_dec_set_format (GstAudioDecoder * dec, GstCaps * caps) 134 { 135 GstALawDec *alawdec = GST_ALAW_DEC (dec); 136 GstStructure *structure; 137 int rate, channels; 138 GstAudioInfo info; 139 140 structure = gst_caps_get_structure (caps, 0); 141 if (!structure) { 142 GST_ERROR_OBJECT (dec, "failed to get structure from caps"); 143 return FALSE; 144 } 145 146 if (!gst_structure_get_int (structure, "rate", &rate)) { 147 GST_ERROR_OBJECT (dec, "failed to find field rate in input caps"); 148 return FALSE; 149 } 150 151 if (!gst_structure_get_int (structure, "channels", &channels)) { 152 GST_ERROR_OBJECT (dec, "failed to find field channels in input caps"); 153 return FALSE; 154 } 155 156 gst_audio_info_init (&info); 157 gst_audio_info_set_format (&info, GST_AUDIO_FORMAT_S16, rate, channels, NULL); 158 159 GST_DEBUG_OBJECT (alawdec, "rate=%d, channels=%d", rate, channels); 160 161 return gst_audio_decoder_set_output_format (dec, &info); 162 } 163 164 static GstFlowReturn 165 gst_alaw_dec_handle_frame (GstAudioDecoder * dec, GstBuffer * buffer) 166 { 167 GstMapInfo inmap, outmap; 168 gint16 *linear_data; 169 guint8 *alaw_data; 170 gsize alaw_size, linear_size; 171 GstBuffer *outbuf; 172 gint i; 173 174 if (!buffer) { 175 return GST_FLOW_OK; 176 } 177 178 if (!gst_buffer_map (buffer, &inmap, GST_MAP_READ)) { 179 GST_ERROR_OBJECT (dec, "failed to map input buffer"); 180 goto error_failed_map_input_buffer; 181 } 182 183 alaw_data = inmap.data; 184 alaw_size = inmap.size; 185 186 linear_size = alaw_size * 2; 187 188 outbuf = gst_audio_decoder_allocate_output_buffer (dec, linear_size); 189 if (!gst_buffer_map (outbuf, &outmap, GST_MAP_WRITE)) { 190 GST_ERROR_OBJECT (dec, "failed to map input buffer"); 191 goto error_failed_map_output_buffer; 192 } 193 194 linear_data = (gint16 *) outmap.data; 195 for (i = 0; i < alaw_size; i++) { 196 linear_data[i] = alaw_to_s16 (alaw_data[i]); 197 } 198 199 gst_buffer_unmap (outbuf, &outmap); 200 gst_buffer_unmap (buffer, &inmap); 201 202 return gst_audio_decoder_finish_frame (dec, outbuf, -1); 203 204 error_failed_map_output_buffer: 205 gst_buffer_unref (outbuf); 206 gst_buffer_unmap (buffer, &inmap); 207 208 error_failed_map_input_buffer: 209 return GST_FLOW_ERROR; 210 } 211 212 static gboolean 213 gst_alaw_dec_start (GstAudioDecoder * dec) 214 { 215 gst_audio_decoder_set_estimate_rate (dec, TRUE); 216 217 return TRUE; 218 } 219 220 static void 221 gst_alaw_dec_class_init (GstALawDecClass * klass) 222 { 223 GstElementClass *element_class = (GstElementClass *) klass; 224 GstAudioDecoderClass *audiodec_class = GST_AUDIO_DECODER_CLASS (klass); 225 226 gst_element_class_add_static_pad_template (element_class, 227 &alaw_dec_src_factory); 228 gst_element_class_add_static_pad_template (element_class, 229 &alaw_dec_sink_factory); 230 231 audiodec_class->start = GST_DEBUG_FUNCPTR (gst_alaw_dec_start); 232 audiodec_class->set_format = GST_DEBUG_FUNCPTR (gst_alaw_dec_set_format); 233 audiodec_class->handle_frame = GST_DEBUG_FUNCPTR (gst_alaw_dec_handle_frame); 234 235 gst_element_class_set_static_metadata (element_class, "A Law audio decoder", 236 "Codec/Decoder/Audio", 237 "Convert 8bit A law to 16bit PCM", 238 "Zaheer Abbas Merali <zaheerabbas at merali dot org>"); 239 240 GST_DEBUG_CATEGORY_INIT (alaw_dec_debug, "alawdec", 0, "A Law audio decoder"); 241 } 242 243 static void 244 gst_alaw_dec_init (GstALawDec * alawdec) 245 { 246 gst_audio_decoder_set_needs_format (GST_AUDIO_DECODER (alawdec), TRUE); 247 gst_audio_decoder_set_use_default_pad_acceptcaps (GST_AUDIO_DECODER_CAST 248 (alawdec), TRUE); 249 GST_PAD_SET_ACCEPT_TEMPLATE (GST_AUDIO_DECODER_SINK_PAD (alawdec)); 250 }