3 * Copyright (c) 2001 Fabrice Bellard.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser 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.
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 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
27 /* from g711.c by SUN microsystems (unrestricted use) */
29 #define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
30 #define QUANT_MASK (0xf) /* Quantization field mask. */
31 #define NSEGS (8) /* Number of A-law segments. */
32 #define SEG_SHIFT (4) /* Left shift for segment number. */
33 #define SEG_MASK (0x70) /* Segment field mask. */
35 #define BIAS (0x84) /* Bias for linear code. */
38 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
41 static int alaw2linear(unsigned char a_val)
48 t = (a_val & QUANT_MASK) << 4;
49 seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
61 return ((a_val & SIGN_BIT) ? t : -t);
64 static int ulaw2linear(unsigned char u_val)
68 /* Complement to obtain normal u-law value. */
72 * Extract and bias the quantization bits. Then
73 * shift up by the segment number and subtract out the bias.
75 t = ((u_val & QUANT_MASK) << 3) + BIAS;
76 t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
78 return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
81 /* 16384 entries per table */
82 static uint8_t *linear_to_alaw = NULL;
83 static int linear_to_alaw_ref = 0;
85 static uint8_t *linear_to_ulaw = NULL;
86 static int linear_to_ulaw_ref = 0;
88 static void build_xlaw_table(uint8_t *linear_to_xlaw,
89 int (*xlaw2linear)(unsigned char),
97 v1 = xlaw2linear(i ^ mask);
98 v2 = xlaw2linear((i + 1) ^ mask);
99 v = (v1 + v2 + 4) >> 3;
104 linear_to_xlaw[8192 + j] = (i ^ mask);
106 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
109 linear_to_xlaw[0] = linear_to_xlaw[1];
112 static int pcm_encode_init(AVCodecContext *avctx)
114 avctx->frame_size = 1;
115 switch(avctx->codec->id) {
116 case CODEC_ID_PCM_ALAW:
117 if (linear_to_alaw_ref == 0) {
118 linear_to_alaw = av_malloc(16384);
121 build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
123 linear_to_alaw_ref++;
125 case CODEC_ID_PCM_MULAW:
126 if (linear_to_ulaw_ref == 0) {
127 linear_to_ulaw = av_malloc(16384);
130 build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
132 linear_to_ulaw_ref++;
138 avctx->coded_frame= avcodec_alloc_frame();
139 avctx->coded_frame->key_frame= 1;
144 static int pcm_encode_close(AVCodecContext *avctx)
146 av_freep(&avctx->coded_frame);
148 switch(avctx->codec->id) {
149 case CODEC_ID_PCM_ALAW:
150 if (--linear_to_alaw_ref == 0)
151 av_free(linear_to_alaw);
153 case CODEC_ID_PCM_MULAW:
154 if (--linear_to_ulaw_ref == 0)
155 av_free(linear_to_ulaw);
158 /* nothing to free */
164 static int pcm_encode_frame(AVCodecContext *avctx,
165 unsigned char *frame, int buf_size, void *data)
167 int n, sample_size, v;
171 switch(avctx->codec->id) {
172 case CODEC_ID_PCM_S16LE:
173 case CODEC_ID_PCM_S16BE:
174 case CODEC_ID_PCM_U16LE:
175 case CODEC_ID_PCM_U16BE:
182 n = buf_size / sample_size;
186 switch(avctx->codec->id) {
187 case CODEC_ID_PCM_S16LE:
195 case CODEC_ID_PCM_S16BE:
203 case CODEC_ID_PCM_U16LE:
212 case CODEC_ID_PCM_U16BE:
221 case CODEC_ID_PCM_S8:
228 case CODEC_ID_PCM_U8:
231 dst[0] = (v >> 8) + 128;
235 case CODEC_ID_PCM_ALAW:
238 dst[0] = linear_to_alaw[(v + 32768) >> 2];
242 case CODEC_ID_PCM_MULAW:
245 dst[0] = linear_to_ulaw[(v + 32768) >> 2];
252 //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
257 typedef struct PCMDecode {
261 static int pcm_decode_init(AVCodecContext * avctx)
263 PCMDecode *s = avctx->priv_data;
266 switch(avctx->codec->id) {
267 case CODEC_ID_PCM_ALAW:
269 s->table[i] = alaw2linear(i);
271 case CODEC_ID_PCM_MULAW:
273 s->table[i] = ulaw2linear(i);
281 static int pcm_decode_frame(AVCodecContext *avctx,
282 void *data, int *data_size,
283 uint8_t *buf, int buf_size)
285 PCMDecode *s = avctx->priv_data;
293 switch(avctx->codec->id) {
294 case CODEC_ID_PCM_S16LE:
297 *samples++ = src[0] | (src[1] << 8);
301 case CODEC_ID_PCM_S16BE:
304 *samples++ = (src[0] << 8) | src[1];
308 case CODEC_ID_PCM_U16LE:
311 *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
315 case CODEC_ID_PCM_U16BE:
318 *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
322 case CODEC_ID_PCM_S8:
325 *samples++ = src[0] << 8;
329 case CODEC_ID_PCM_U8:
332 *samples++ = ((int)src[0] - 128) << 8;
336 case CODEC_ID_PCM_ALAW:
337 case CODEC_ID_PCM_MULAW:
340 *samples++ = s->table[src[0]];
348 *data_size = (uint8_t *)samples - (uint8_t *)data;
352 #define PCM_CODEC(id, name) \
353 AVCodec name ## _encoder = { \
363 AVCodec name ## _decoder = { \
374 PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
375 PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
376 PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
377 PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
378 PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
379 PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
380 PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
381 PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);