--- /dev/null
+/*
+ * PCM codecs
+ * Copyright (c) 2001 Fabrice Bellard.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/**
+ * @file pcm.c
+ * PCM codecs
+ */
+
+#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_t *linear_to_alaw = NULL;
+static int linear_to_alaw_ref = 0;
+
+static uint8_t *linear_to_ulaw = NULL;
+static int linear_to_ulaw_ref = 0;
+
+static void build_xlaw_table(uint8_t *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<v;j++) {
+ linear_to_xlaw[8192 + j] = (i ^ mask);
+ if (j > 0)
+ linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
+ }
+ }
+ linear_to_xlaw[0] = linear_to_xlaw[1];
+}
+
+static int pcm_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 = av_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 = av_malloc(16384);
+ if (!linear_to_ulaw)
+ return -1;
+ build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
+ }
+ linear_to_ulaw_ref++;
+ break;
+ default:
+ break;
+ }
+
+ avctx->coded_frame= avcodec_alloc_frame();
+ avctx->coded_frame->key_frame= 1;
+
+ return 0;
+}
+
+static int pcm_encode_close(AVCodecContext *avctx)
+{
+ av_freep(&avctx->coded_frame);
+
+ switch(avctx->codec->id) {
+ case CODEC_ID_PCM_ALAW:
+ if (--linear_to_alaw_ref == 0)
+ av_free(linear_to_alaw);
+ break;
+ case CODEC_ID_PCM_MULAW:
+ if (--linear_to_ulaw_ref == 0)
+ av_free(linear_to_ulaw);
+ break;
+ default:
+ /* nothing to free */
+ break;
+ }
+ return 0;
+}
+
+static int pcm_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 >> 8;
+ dst++;
+ }
+ break;
+ case CODEC_ID_PCM_U8:
+ for(;n>0;n--) {
+ v = *samples++;
+ dst[0] = (v >> 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;
+ }
+ //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
+
+ return dst - frame;
+}
+
+typedef struct PCMDecode {
+ short table[256];
+} PCMDecode;
+
+static int pcm_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 pcm_decode_frame(AVCodecContext *avctx,
+ void *data, int *data_size,
+ uint8_t *buf, int buf_size)
+{
+ PCMDecode *s = avctx->priv_data;
+ int n;
+ short *samples;
+ uint8_t *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_t *)samples - (uint8_t *)data;
+ return src - buf;
+}
+
+#define PCM_CODEC(id, name) \
+AVCodec name ## _encoder = { \
+ #name, \
+ CODEC_TYPE_AUDIO, \
+ id, \
+ 0, \
+ pcm_encode_init, \
+ pcm_encode_frame, \
+ pcm_encode_close, \
+ NULL, \
+}; \
+AVCodec name ## _decoder = { \
+ #name, \
+ CODEC_TYPE_AUDIO, \
+ id, \
+ sizeof(PCMDecode), \
+ pcm_decode_init, \
+ NULL, \
+ NULL, \
+ pcm_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);
+
+#undef PCM_CODEC
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