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;
49 seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
50 if(seg) t= (t + t + 1 + 32) << (seg + 2);
51 else t= (t + t + 1 ) << 3;
53 return ((a_val & SIGN_BIT) ? t : -t);
56 static int ulaw2linear(unsigned char u_val)
60 /* Complement to obtain normal u-law value. */
64 * Extract and bias the quantization bits. Then
65 * shift up by the segment number and subtract out the bias.
67 t = ((u_val & QUANT_MASK) << 3) + BIAS;
68 t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
70 return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
73 /* 16384 entries per table */
74 static uint8_t *linear_to_alaw = NULL;
75 static int linear_to_alaw_ref = 0;
77 static uint8_t *linear_to_ulaw = NULL;
78 static int linear_to_ulaw_ref = 0;
80 static void build_xlaw_table(uint8_t *linear_to_xlaw,
81 int (*xlaw2linear)(unsigned char),
89 v1 = xlaw2linear(i ^ mask);
90 v2 = xlaw2linear((i + 1) ^ mask);
91 v = (v1 + v2 + 4) >> 3;
96 linear_to_xlaw[8192 + j] = (i ^ mask);
98 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
101 linear_to_xlaw[0] = linear_to_xlaw[1];
104 static int pcm_encode_init(AVCodecContext *avctx)
106 avctx->frame_size = 1;
107 switch(avctx->codec->id) {
108 case CODEC_ID_PCM_ALAW:
109 if (linear_to_alaw_ref == 0) {
110 linear_to_alaw = av_malloc(16384);
113 build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
115 linear_to_alaw_ref++;
117 case CODEC_ID_PCM_MULAW:
118 if (linear_to_ulaw_ref == 0) {
119 linear_to_ulaw = av_malloc(16384);
122 build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
124 linear_to_ulaw_ref++;
130 avctx->coded_frame= avcodec_alloc_frame();
131 avctx->coded_frame->key_frame= 1;
136 static int pcm_encode_close(AVCodecContext *avctx)
138 av_freep(&avctx->coded_frame);
140 switch(avctx->codec->id) {
141 case CODEC_ID_PCM_ALAW:
142 if (--linear_to_alaw_ref == 0)
143 av_free(linear_to_alaw);
145 case CODEC_ID_PCM_MULAW:
146 if (--linear_to_ulaw_ref == 0)
147 av_free(linear_to_ulaw);
150 /* nothing to free */
156 static int pcm_encode_frame(AVCodecContext *avctx,
157 unsigned char *frame, int buf_size, void *data)
159 int n, sample_size, v;
163 switch(avctx->codec->id) {
164 case CODEC_ID_PCM_S16LE:
165 case CODEC_ID_PCM_S16BE:
166 case CODEC_ID_PCM_U16LE:
167 case CODEC_ID_PCM_U16BE:
174 n = buf_size / sample_size;
178 switch(avctx->codec->id) {
179 case CODEC_ID_PCM_S16LE:
187 case CODEC_ID_PCM_S16BE:
195 case CODEC_ID_PCM_U16LE:
204 case CODEC_ID_PCM_U16BE:
213 case CODEC_ID_PCM_S8:
220 case CODEC_ID_PCM_U8:
223 dst[0] = (v >> 8) + 128;
227 case CODEC_ID_PCM_ALAW:
230 dst[0] = linear_to_alaw[(v + 32768) >> 2];
234 case CODEC_ID_PCM_MULAW:
237 dst[0] = linear_to_ulaw[(v + 32768) >> 2];
244 //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
249 typedef struct PCMDecode {
253 static int pcm_decode_init(AVCodecContext * avctx)
255 PCMDecode *s = avctx->priv_data;
258 switch(avctx->codec->id) {
259 case CODEC_ID_PCM_ALAW:
261 s->table[i] = alaw2linear(i);
263 case CODEC_ID_PCM_MULAW:
265 s->table[i] = ulaw2linear(i);
273 static int pcm_decode_frame(AVCodecContext *avctx,
274 void *data, int *data_size,
275 uint8_t *buf, int buf_size)
277 PCMDecode *s = avctx->priv_data;
285 switch(avctx->codec->id) {
286 case CODEC_ID_PCM_S16LE:
289 *samples++ = src[0] | (src[1] << 8);
293 case CODEC_ID_PCM_S16BE:
296 *samples++ = (src[0] << 8) | src[1];
300 case CODEC_ID_PCM_U16LE:
303 *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
307 case CODEC_ID_PCM_U16BE:
310 *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
314 case CODEC_ID_PCM_S8:
317 *samples++ = src[0] << 8;
321 case CODEC_ID_PCM_U8:
324 *samples++ = ((int)src[0] - 128) << 8;
328 case CODEC_ID_PCM_ALAW:
329 case CODEC_ID_PCM_MULAW:
332 *samples++ = s->table[src[0]];
339 *data_size = (uint8_t *)samples - (uint8_t *)data;
343 #define PCM_CODEC(id, name) \
344 AVCodec name ## _encoder = { \
354 AVCodec name ## _decoder = { \
365 PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
366 PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
367 PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
368 PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
369 PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
370 PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
371 PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
372 PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);