added pcm codecs

Originally committed as revision 140 to svn://svn.ffmpeg.org/ffmpeg/trunk

1 files changed, 367 insertions, 0 deletions

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<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 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);