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
21 /* from g711.c by SUN microsystems (unrestricted use) */
23 #define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
24 #define QUANT_MASK (0xf) /* Quantization field mask. */
25 #define NSEGS (8) /* Number of A-law segments. */
26 #define SEG_SHIFT (4) /* Left shift for segment number. */
27 #define SEG_MASK (0x70) /* Segment field mask. */
29 #define BIAS (0x84) /* Bias for linear code. */
32 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
35 static int alaw2linear(unsigned char a_val)
42 t = (a_val & QUANT_MASK) << 4;
43 seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
55 return ((a_val & SIGN_BIT) ? t : -t);
58 static int ulaw2linear(unsigned char u_val)
62 /* Complement to obtain normal u-law value. */
66 * Extract and bias the quantization bits. Then
67 * shift up by the segment number and subtract out the bias.
69 t = ((u_val & QUANT_MASK) << 3) + BIAS;
70 t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
72 return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
75 /* 16384 entries per table */
76 static UINT8 *linear_to_alaw = NULL;
77 static int linear_to_alaw_ref = 0;
79 static UINT8 *linear_to_ulaw = NULL;
80 static int linear_to_ulaw_ref = 0;
82 static void build_xlaw_table(UINT8 *linear_to_xlaw,
83 int (*xlaw2linear)(unsigned char),
91 v1 = xlaw2linear(i ^ mask);
92 v2 = xlaw2linear((i + 1) ^ mask);
93 v = (v1 + v2 + 4) >> 3;
98 linear_to_xlaw[8192 + j] = (i ^ mask);
100 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
103 linear_to_xlaw[0] = linear_to_xlaw[1];
106 static int pcm_encode_init(AVCodecContext *avctx)
108 avctx->frame_size = 1;
109 switch(avctx->codec->id) {
110 case CODEC_ID_PCM_ALAW:
111 if (linear_to_alaw_ref == 0) {
112 linear_to_alaw = av_malloc(16384);
115 build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
117 linear_to_alaw_ref++;
119 case CODEC_ID_PCM_MULAW:
120 if (linear_to_ulaw_ref == 0) {
121 linear_to_ulaw = av_malloc(16384);
124 build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
126 linear_to_ulaw_ref++;
134 static int pcm_encode_close(AVCodecContext *avctx)
136 switch(avctx->codec->id) {
137 case CODEC_ID_PCM_ALAW:
138 if (--linear_to_alaw_ref == 0)
139 av_free(linear_to_alaw);
141 case CODEC_ID_PCM_MULAW:
142 if (--linear_to_ulaw_ref == 0)
143 av_free(linear_to_ulaw);
146 /* nothing to free */
152 static int pcm_encode_frame(AVCodecContext *avctx,
153 unsigned char *frame, int buf_size, void *data)
155 int n, sample_size, v;
159 switch(avctx->codec->id) {
160 case CODEC_ID_PCM_S16LE:
161 case CODEC_ID_PCM_S16BE:
162 case CODEC_ID_PCM_U16LE:
163 case CODEC_ID_PCM_U16BE:
170 n = buf_size / sample_size;
174 switch(avctx->codec->id) {
175 case CODEC_ID_PCM_S16LE:
183 case CODEC_ID_PCM_S16BE:
191 case CODEC_ID_PCM_U16LE:
200 case CODEC_ID_PCM_U16BE:
209 case CODEC_ID_PCM_S8:
216 case CODEC_ID_PCM_U8:
219 dst[0] = (v >> 8) + 128;
223 case CODEC_ID_PCM_ALAW:
226 dst[0] = linear_to_alaw[(v + 32768) >> 2];
230 case CODEC_ID_PCM_MULAW:
233 dst[0] = linear_to_ulaw[(v + 32768) >> 2];
240 avctx->key_frame = 1;
241 //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
246 typedef struct PCMDecode {
250 static int pcm_decode_init(AVCodecContext * avctx)
252 PCMDecode *s = avctx->priv_data;
255 switch(avctx->codec->id) {
256 case CODEC_ID_PCM_ALAW:
258 s->table[i] = alaw2linear(i);
260 case CODEC_ID_PCM_MULAW:
262 s->table[i] = ulaw2linear(i);
270 static int pcm_decode_frame(AVCodecContext *avctx,
271 void *data, int *data_size,
272 UINT8 *buf, int buf_size)
274 PCMDecode *s = avctx->priv_data;
282 switch(avctx->codec->id) {
283 case CODEC_ID_PCM_S16LE:
286 *samples++ = src[0] | (src[1] << 8);
290 case CODEC_ID_PCM_S16BE:
293 *samples++ = (src[0] << 8) | src[1];
297 case CODEC_ID_PCM_U16LE:
300 *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
304 case CODEC_ID_PCM_U16BE:
307 *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
311 case CODEC_ID_PCM_S8:
314 *samples++ = src[0] << 8;
318 case CODEC_ID_PCM_U8:
321 *samples++ = ((int)src[0] - 128) << 8;
325 case CODEC_ID_PCM_ALAW:
326 case CODEC_ID_PCM_MULAW:
329 *samples++ = s->table[src[0]];
337 *data_size = (UINT8 *)samples - (UINT8 *)data;
341 #define PCM_CODEC(id, name) \
342 AVCodec name ## _encoder = { \
352 AVCodec name ## _decoder = { \
363 PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
364 PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
365 PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
366 PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
367 PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
368 PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
369 PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
370 PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);