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			373 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			373 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * PCM codecs
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|  * Copyright (c) 2001 Fabrice Bellard.
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|  *
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|  * This library is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Lesser General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2 of the License, or (at your option) any later version.
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|  *
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|  * This library is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with this library; if not, write to the Free Software
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|  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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|  */
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| #include "avcodec.h"
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| 
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| /* from g711.c by SUN microsystems (unrestricted use) */
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| 
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| #define	SIGN_BIT	(0x80)		/* Sign bit for a A-law byte. */
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| #define	QUANT_MASK	(0xf)		/* Quantization field mask. */
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| #define	NSEGS		(8)		/* Number of A-law segments. */
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| #define	SEG_SHIFT	(4)		/* Left shift for segment number. */
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| #define	SEG_MASK	(0x70)		/* Segment field mask. */
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| 
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| #define	BIAS		(0x84)		/* Bias for linear code. */
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| 
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| /*
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|  * alaw2linear() - Convert an A-law value to 16-bit linear PCM
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|  *
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|  */
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| static int alaw2linear(unsigned char	a_val)
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| {
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| 	int		t;
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| 	int		seg;
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| 
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| 	a_val ^= 0x55;
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| 
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| 	t = (a_val & QUANT_MASK) << 4;
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| 	seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
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| 	switch (seg) {
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| 	case 0:
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| 		t += 8;
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| 		break;
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| 	case 1:
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| 		t += 0x108;
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| 		break;
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| 	default:
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| 		t += 0x108;
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| 		t <<= seg - 1;
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| 	}
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| 	return ((a_val & SIGN_BIT) ? t : -t);
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| }
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| 
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| static int ulaw2linear(unsigned char	u_val)
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| {
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| 	int		t;
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| 
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| 	/* Complement to obtain normal u-law value. */
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| 	u_val = ~u_val;
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| 
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| 	/*
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| 	 * Extract and bias the quantization bits. Then
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| 	 * shift up by the segment number and subtract out the bias.
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| 	 */
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| 	t = ((u_val & QUANT_MASK) << 3) + BIAS;
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| 	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
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| 
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| 	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
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| }
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| 
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| /* 16384 entries per table */
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| static UINT8 *linear_to_alaw = NULL;
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| static int linear_to_alaw_ref = 0;
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| 
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| static UINT8 *linear_to_ulaw = NULL;
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| static int linear_to_ulaw_ref = 0;
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| 
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| static void build_xlaw_table(UINT8 *linear_to_xlaw, 
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|                              int (*xlaw2linear)(unsigned char),
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|                              int mask) 
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| {
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|     int i, j, v, v1, v2;
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| 
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|     j = 0;
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|     for(i=0;i<128;i++) {
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|         if (i != 127) {
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|             v1 = xlaw2linear(i ^ mask);
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|             v2 = xlaw2linear((i + 1) ^ mask);
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|             v = (v1 + v2 + 4) >> 3;
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|         } else {
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|             v = 8192;
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|         }
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|         for(;j<v;j++) {
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|             linear_to_xlaw[8192 + j] = (i ^ mask);
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|             if (j > 0)
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|                 linear_to_xlaw[8192 - j] = (i ^ (mask ^ 0x80));
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|         }
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|     }
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|     linear_to_xlaw[0] = linear_to_xlaw[1];
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| }
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| 
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| static int pcm_encode_init(AVCodecContext *avctx)
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| {
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|     avctx->frame_size = 1;
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|     switch(avctx->codec->id) {
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|     case CODEC_ID_PCM_ALAW:
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|         if (linear_to_alaw_ref == 0) {
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|             linear_to_alaw = av_malloc(16384);
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|             if (!linear_to_alaw)
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|                 return -1;
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|             build_xlaw_table(linear_to_alaw, alaw2linear, 0xd5);
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|         }
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|         linear_to_alaw_ref++;
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|         break;
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|     case CODEC_ID_PCM_MULAW:
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|         if (linear_to_ulaw_ref == 0) {
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|             linear_to_ulaw = av_malloc(16384);
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|             if (!linear_to_ulaw)
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|                 return -1;
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|             build_xlaw_table(linear_to_ulaw, ulaw2linear, 0xff);
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|         }
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|         linear_to_ulaw_ref++;
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|         break;
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|     default:
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|         break;
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|     }
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|     return 0;
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| }
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| 
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| static int pcm_encode_close(AVCodecContext *avctx)
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| {
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|     switch(avctx->codec->id) {
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|     case CODEC_ID_PCM_ALAW:
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|         if (--linear_to_alaw_ref == 0)
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|             av_free(linear_to_alaw);
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|         break;
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|     case CODEC_ID_PCM_MULAW:
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|         if (--linear_to_ulaw_ref == 0)
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|             av_free(linear_to_ulaw);
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|         break;
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|     default:
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|         /* nothing to free */
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|         break;
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|     }
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|     return 0;
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| }
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| 
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| static int pcm_encode_frame(AVCodecContext *avctx,
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| 			    unsigned char *frame, int buf_size, void *data)
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| {
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|     int n, sample_size, v;
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|     short *samples;
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|     unsigned char *dst;
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| 
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|     switch(avctx->codec->id) {
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|     case CODEC_ID_PCM_S16LE:
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|     case CODEC_ID_PCM_S16BE:
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|     case CODEC_ID_PCM_U16LE:
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|     case CODEC_ID_PCM_U16BE:
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|         sample_size = 2;
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|         break;
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|     default:
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|         sample_size = 1;
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|         break;
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|     }
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|     n = buf_size / sample_size;
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|     samples = data;
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|     dst = frame;
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| 
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|     switch(avctx->codec->id) {
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|     case CODEC_ID_PCM_S16LE:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             dst[0] = v & 0xff;
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|             dst[1] = v >> 8;
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|             dst += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_S16BE:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             dst[0] = v >> 8;
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|             dst[1] = v;
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|             dst += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_U16LE:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             v += 0x8000;
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|             dst[0] = v & 0xff;
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|             dst[1] = v >> 8;
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|             dst += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_U16BE:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             v += 0x8000;
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|             dst[0] = v >> 8;
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|             dst[1] = v;
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|             dst += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_S8:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             dst[0] = v >> 8;
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|             dst++;
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|         }
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|         break;
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|     case CODEC_ID_PCM_U8:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             dst[0] = (v >> 8) + 128;
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|             dst++;
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|         }
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|         break;
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|     case CODEC_ID_PCM_ALAW:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             dst[0] = linear_to_alaw[(v + 32768) >> 2];
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|             dst++;
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|         }
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|         break;
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|     case CODEC_ID_PCM_MULAW:
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|         for(;n>0;n--) {
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|             v = *samples++;
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|             dst[0] = linear_to_ulaw[(v + 32768) >> 2];
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|             dst++;
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|         }
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|         break;
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|     default:
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|         return -1;
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|     }
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|     avctx->key_frame = 1;
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|     //avctx->frame_size = (dst - frame) / (sample_size * avctx->channels);
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| 
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|     return dst - frame;
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| }
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| 
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| typedef struct PCMDecode {
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|     short table[256];
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| } PCMDecode;
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| 
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| static int pcm_decode_init(AVCodecContext * avctx)
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| {
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|     PCMDecode *s = avctx->priv_data;
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|     int i;
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| 
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|     switch(avctx->codec->id) {
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|     case CODEC_ID_PCM_ALAW:
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|         for(i=0;i<256;i++)
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|             s->table[i] = alaw2linear(i);
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|         break;
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|     case CODEC_ID_PCM_MULAW:
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|         for(i=0;i<256;i++)
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|             s->table[i] = ulaw2linear(i);
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|         break;
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|     default:
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|         break;
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|     }
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|     return 0;
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| }
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| 
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| static int pcm_decode_frame(AVCodecContext *avctx,
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| 			    void *data, int *data_size,
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| 			    UINT8 *buf, int buf_size)
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| {
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|     PCMDecode *s = avctx->priv_data;
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|     int n;
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|     short *samples;
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|     UINT8 *src;
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| 
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|     samples = data;
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|     src = buf;
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| 
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|     switch(avctx->codec->id) {
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|     case CODEC_ID_PCM_S16LE:
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|         n = buf_size >> 1;
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|         for(;n>0;n--) {
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|             *samples++ = src[0] | (src[1] << 8);
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|             src += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_S16BE:
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|         n = buf_size >> 1;
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|         for(;n>0;n--) {
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|             *samples++ = (src[0] << 8) | src[1];
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|             src += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_U16LE:
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|         n = buf_size >> 1;
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|         for(;n>0;n--) {
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|             *samples++ = (src[0] | (src[1] << 8)) - 0x8000;
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|             src += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_U16BE:
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|         n = buf_size >> 1;
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|         for(;n>0;n--) {
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|             *samples++ = ((src[0] << 8) | src[1]) - 0x8000;
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|             src += 2;
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|         }
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|         break;
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|     case CODEC_ID_PCM_S8:
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|         n = buf_size;
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|         for(;n>0;n--) {
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|             *samples++ = src[0] << 8;
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|             src++;
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|         }
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|         break;
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|     case CODEC_ID_PCM_U8:
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|         n = buf_size;
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|         for(;n>0;n--) {
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|             *samples++ = ((int)src[0] - 128) << 8;
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|             src++;
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|         }
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|         break;
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|     case CODEC_ID_PCM_ALAW:
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|     case CODEC_ID_PCM_MULAW:
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|         n = buf_size;
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|         for(;n>0;n--) {
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|             *samples++ = s->table[src[0]];
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|             src++;
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|         }
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|         break;
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|     default:
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|         *data_size = 0;
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|         return -1;
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|     }
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|     *data_size = (UINT8 *)samples - (UINT8 *)data;
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|     return src - buf;
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| }
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| 
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| #define PCM_CODEC(id, name)                     \
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| AVCodec name ## _encoder = {                    \
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|     #name,                                      \
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|     CODEC_TYPE_AUDIO,                           \
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|     id,                                         \
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|     0,                                          \
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|     pcm_encode_init,				\
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|     pcm_encode_frame,				\
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|     pcm_encode_close,				\
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|     NULL,                                       \
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| };                                              \
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| AVCodec name ## _decoder = {                    \
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|     #name,                                      \
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|     CODEC_TYPE_AUDIO,                           \
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|     id,                                         \
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|     sizeof(PCMDecode),                          \
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|     pcm_decode_init,				\
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|     NULL,                                       \
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|     NULL,                                       \
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|     pcm_decode_frame,                           \
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| };
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| 
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| PCM_CODEC(CODEC_ID_PCM_S16LE, pcm_s16le);
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| PCM_CODEC(CODEC_ID_PCM_S16BE, pcm_s16be);
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| PCM_CODEC(CODEC_ID_PCM_U16LE, pcm_u16le);
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| PCM_CODEC(CODEC_ID_PCM_U16BE, pcm_u16be);
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| PCM_CODEC(CODEC_ID_PCM_S8, pcm_s8);
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| PCM_CODEC(CODEC_ID_PCM_U8, pcm_u8);
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| PCM_CODEC(CODEC_ID_PCM_ALAW, pcm_alaw);
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| PCM_CODEC(CODEC_ID_PCM_MULAW, pcm_mulaw);
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| 
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| #undef PCM_CODEC
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