From a96b68b717ee7c93833eb7c07900456e055ef29d Mon Sep 17 00:00:00 2001 From: Fabrice Bellard Date: Sun, 23 Sep 2001 17:16:51 +0000 Subject: added pcm codecs Originally committed as revision 140 to svn://svn.ffmpeg.org/ffmpeg/trunk --- libavcodec/pcm.c | 367 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 367 insertions(+) create mode 100644 libavcodec/pcm.c (limited to 'libavcodec/pcm.c') diff --git a/libavcodec/pcm.c b/libavcodec/pcm.c new file mode 100644 index 0000000000..a3895f5b51 --- /dev/null +++ b/libavcodec/pcm.c @@ -0,0 +1,367 @@ +/* + * PCM codecs + * Copyright (c) 2001 Gerard Lantau. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ +#include "avcodec.h" + +/* from g711.c by SUN microsystems (unrestricted use) */ + +#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */ +#define QUANT_MASK (0xf) /* Quantization field mask. */ +#define NSEGS (8) /* Number of A-law segments. */ +#define SEG_SHIFT (4) /* Left shift for segment number. */ +#define SEG_MASK (0x70) /* Segment field mask. */ + +#define BIAS (0x84) /* Bias for linear code. */ + +/* + * alaw2linear() - Convert an A-law value to 16-bit linear PCM + * + */ +static int alaw2linear(unsigned char a_val) +{ + int t; + int seg; + + a_val ^= 0x55; + + t = (a_val & QUANT_MASK) << 4; + seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT; + switch (seg) { + case 0: + t += 8; + break; + case 1: + t += 0x108; + break; + default: + t += 0x108; + t <<= seg - 1; + } + return ((a_val & SIGN_BIT) ? t : -t); +} + +static int ulaw2linear(unsigned char u_val) +{ + int t; + + /* Complement to obtain normal u-law value. */ + u_val = ~u_val; + + /* + * Extract and bias the quantization bits. Then + * shift up by the segment number and subtract out the bias. + */ + t = ((u_val & QUANT_MASK) << 3) + BIAS; + t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT; + + return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS)); +} + +/* 16384 entries per table */ +static UINT8 *linear_to_alaw = NULL; +static int linear_to_alaw_ref = 0; + +static UINT8 *linear_to_ulaw = NULL; +static int linear_to_ulaw_ref = 0; + +static void build_xlaw_table(UINT8 *linear_to_xlaw, + int (*xlaw2linear)(unsigned char), + int mask) +{ + int i, j, v, v1, v2; + + j = 0; + for(i=0;i<128;i++) { + if (i != 127) { + v1 = xlaw2linear(i ^ mask); + v2 = xlaw2linear((i + 1) ^ mask); + v = (v1 + v2 + 4) >> 3; + } else { + v = 8192; + } + for(;j 0) + linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80)); + } + } + linear_to_xlaw[0] = linear_to_xlaw[1]; +} + +static int encode_init(AVCodecContext *avctx) +{ + avctx->frame_size = 1; + switch(avctx->codec->id) { + case CODEC_ID_PCM_ALAW: + if (linear_to_alaw_ref == 0) { + linear_to_alaw = malloc(16384); + if (!linear_to_alaw) + return -1; + build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5); + } + linear_to_alaw_ref++; + break; + case CODEC_ID_PCM_MULAW: + if (linear_to_ulaw_ref == 0) { + linear_to_ulaw = malloc(16384); + if (!linear_to_ulaw) + return -1; + build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff); + } + linear_to_ulaw_ref++; + break; + default: + break; + } + return 0; +} + +static int encode_close(AVCodecContext *avctx) +{ + switch(avctx->codec->id) { + case CODEC_ID_PCM_ALAW: + if (--linear_to_alaw_ref == 0) + free(linear_to_alaw); + break; + case CODEC_ID_PCM_MULAW: + if (--linear_to_ulaw_ref == 0) + free(linear_to_ulaw); + break; + default: + /* nothing to free */ + break; + } + return 0; +} + +static int encode_frame(AVCodecContext *avctx, + unsigned char *frame, int buf_size, void *data) +{ + int n, sample_size, v; + short *samples; + unsigned char *dst; + + switch(avctx->codec->id) { + case CODEC_ID_PCM_S16LE: + case CODEC_ID_PCM_S16BE: + case CODEC_ID_PCM_U16LE: + case CODEC_ID_PCM_U16BE: + sample_size = 2; + break; + default: + sample_size = 1; + break; + } + n = buf_size / sample_size; + samples = data; + dst = frame; + + switch(avctx->codec->id) { + case CODEC_ID_PCM_S16LE: + for(;n>0;n--) { + v = *samples++; + dst[0] = v & 0xff; + dst[1] = v >> 8; + dst += 2; + } + break; + case CODEC_ID_PCM_S16BE: + for(;n>0;n--) { + v = *samples++; + dst[0] = v >> 8; + dst[1] = v; + dst += 2; + } + break; + case CODEC_ID_PCM_U16LE: + for(;n>0;n--) { + v = *samples++; + v += 0x8000; + dst[0] = v & 0xff; + dst[1] = v >> 8; + dst += 2; + } + break; + case CODEC_ID_PCM_U16BE: + for(;n>0;n--) { + v = *samples++; + v += 0x8000; + dst[0] = v >> 8; + dst[1] = v; + dst += 2; + } + break; + case CODEC_ID_PCM_S8: + for(;n>0;n--) { + v = *samples++; + dst[0] = (v + 128) >> 8; + dst++; + } + break; + case CODEC_ID_PCM_U8: + for(;n>0;n--) { + v = *samples++; + dst[0] = ((v + 128) >> 8) + 128; + dst++; + } + break; + case CODEC_ID_PCM_ALAW: + for(;n>0;n--) { + v = *samples++; + dst[0] = linear_to_alaw[(v + 32768) >> 2]; + dst++; + } + break; + case CODEC_ID_PCM_MULAW: + for(;n>0;n--) { + v = *samples++; + dst[0] = linear_to_ulaw[(v + 32768) >> 2]; + dst++; + } + break; + default: + return -1; + } + return dst - frame; +} + +typedef struct PCMDecode { + short table[256]; +} PCMDecode; + +static int decode_init(AVCodecContext * avctx) +{ + PCMDecode *s = avctx->priv_data; + int i; + + switch(avctx->codec->id) { + case CODEC_ID_PCM_ALAW: + for(i=0;i<256;i++) + s->table[i] = alaw2linear(i); + break; + case CODEC_ID_PCM_MULAW: + for(i=0;i<256;i++) + s->table[i] = ulaw2linear(i); + break; + default: + break; + } + return 0; +} + +static int decode_frame(AVCodecContext *avctx, + void *data, int *data_size, + UINT8 *buf, int buf_size) +{ + PCMDecode *s = avctx->priv_data; + int n; + short *samples; + UINT8 *src; + + samples = data; + src = buf; + + switch(avctx->codec->id) { + case CODEC_ID_PCM_S16LE: + n = buf_size >> 1; + for(;n>0;n--) { + *samples++ = src[0] | (src[1] << 8); + src += 2; + } + break; + case CODEC_ID_PCM_S16BE: + n = buf_size >> 1; + for(;n>0;n--) { + *samples++ = (src[0] << 8) | src[1]; + src += 2; + } + break; + case CODEC_ID_PCM_U16LE: + n = buf_size >> 1; + for(;n>0;n--) { + *samples++ = (src[0] | (src[1] << 8)) - 0x8000; + src += 2; + } + break; + case CODEC_ID_PCM_U16BE: + n = buf_size >> 1; + for(;n>0;n--) { + *samples++ = ((src[0] << 8) | src[1]) - 0x8000; + src += 2; + } + break; + case CODEC_ID_PCM_S8: + n = buf_size; + for(;n>0;n--) { + *samples++ = src[0] << 8; + src++; + } + break; + case CODEC_ID_PCM_U8: + n = buf_size; + for(;n>0;n--) { + *samples++ = ((int)src[0] - 128) << 8; + src++; + } + break; + case CODEC_ID_PCM_ALAW: + case CODEC_ID_PCM_MULAW: + n = buf_size; + for(;n>0;n--) { + *samples++ = s->table[src[0]]; + src++; + } + break; + default: + *data_size = 0; + return -1; + } + *data_size = (UINT8 *)samples - (UINT8 *)data; + return src - buf; +} + +#define PCM_CODEC(id, name) \ +AVCodec name ## _encoder = { \ + #name, \ + CODEC_TYPE_AUDIO, \ + id, \ + 0, \ + encode_init, \ + encode_frame, \ + encode_close, \ + NULL, \ +}; \ +AVCodec name ## _decoder = { \ + #name, \ + CODEC_TYPE_AUDIO, \ + id, \ + sizeof(PCMDecode), \ + decode_init, \ + NULL, \ + NULL, \ + decode_frame, \ +}; + +PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le); +PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be); +PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le); +PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be); +PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8); +PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8); +PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw); +PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw); -- cgit v1.2.3