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/* ----------------------------------------------------------------------
Copyright (C) 2001 Juha Yrjölä (jyrjola@cc.hut.fi)
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 <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "ac3-iec958.h"
struct frmsize_s
{
unsigned short bit_rate;
unsigned short frm_size[3];
};
static const struct frmsize_s frmsizecod_tbl[64] =
{
{ 32 ,{64 ,69 ,96 } },
{ 32 ,{64 ,70 ,96 } },
{ 40 ,{80 ,87 ,120 } },
{ 40 ,{80 ,88 ,120 } },
{ 48 ,{96 ,104 ,144 } },
{ 48 ,{96 ,105 ,144 } },
{ 56 ,{112 ,121 ,168 } },
{ 56 ,{112 ,122 ,168 } },
{ 64 ,{128 ,139 ,192 } },
{ 64 ,{128 ,140 ,192 } },
{ 80 ,{160 ,174 ,240 } },
{ 80 ,{160 ,175 ,240 } },
{ 96 ,{192 ,208 ,288 } },
{ 96 ,{192 ,209 ,288 } },
{ 112 ,{224 ,243 ,336 } },
{ 112 ,{224 ,244 ,336 } },
{ 128 ,{256 ,278 ,384 } },
{ 128 ,{256 ,279 ,384 } },
{ 160 ,{320 ,348 ,480 } },
{ 160 ,{320 ,349 ,480 } },
{ 192 ,{384 ,417 ,576 } },
{ 192 ,{384 ,418 ,576 } },
{ 224 ,{448 ,487 ,672 } },
{ 224 ,{448 ,488 ,672 } },
{ 256 ,{512 ,557 ,768 } },
{ 256 ,{512 ,558 ,768 } },
{ 320 ,{640 ,696 ,960 } },
{ 320 ,{640 ,697 ,960 } },
{ 384 ,{768 ,835 ,1152 } },
{ 384 ,{768 ,836 ,1152 } },
{ 448 ,{896 ,975 ,1344 } },
{ 448 ,{896 ,976 ,1344 } },
{ 512 ,{1024 ,1114 ,1536 } },
{ 512 ,{1024 ,1115 ,1536 } },
{ 576 ,{1152 ,1253 ,1728 } },
{ 576 ,{1152 ,1254 ,1728 } },
{ 640 ,{1280 ,1393 ,1920 } },
{ 640 ,{1280 ,1394 ,1920 } }
};
struct syncframe {
struct syncinfo {
unsigned char syncword[2];
unsigned char crc1[2];
unsigned char code;
} syncinfo;
struct bsi {
unsigned char bsidmod;
unsigned char acmod;
} bsi;
};
void ac3_iec958_build_burst(int length, int data_type, int big_endian, unsigned char * data, unsigned char * out)
{
const char sync[4] = { 0x72, 0xF8, 0x1F, 0x4E };
memcpy(out, sync, 4);
if (length)
out[4] = data_type; /* & 0x1F; */
else
out[4] = 0;
out[5] = 0x00;
out[6] = (length*8) & 0xFF;
out[7] = ((length*8) >> 8) & 0xFF;
if (big_endian)
swab(data, out + 8, length);
else
memcpy(data, out + 8, length);
memset(out + 8 + length, 0, 6144 - 8 - length);
}
int ac3_iec958_parse_syncinfo(unsigned char *buf, int size, struct hwac3info *ai, int *skipped)
{
int samplerates[4] = { 48000, 44100, 32000, -1 };
unsigned short sync = 0;
unsigned char *ptr = buf;
int fscod, frmsizecod;
struct syncframe *sf;
sync = buf[0] << 8;
sync |= buf[1];
ptr = buf + 2;
*skipped = 0;
while (sync != 0xb77 && *skipped < size - 8) {
sync <<= 8;
sync |= *ptr;
ptr++;
*skipped += 1;
}
if (sync != 0xb77)
return -1;
ptr -= 2;
sf = (struct syncframe *) ptr;
fscod = (sf->syncinfo.code >> 6) & 0x03;
ai->samplerate = samplerates[fscod];
if (ai->samplerate == -1)
return -1;
frmsizecod = sf->syncinfo.code & 0x3f;
ai->framesize = 2 * frmsizecod_tbl[frmsizecod].frm_size[fscod];
ai->bitrate = frmsizecod_tbl[frmsizecod].bit_rate;
if (((sf->bsi.bsidmod >> 3) & 0x1f) != 0x08)
return -1;
ai->bsmod = sf->bsi.bsidmod & 0x7;
return 0;
}
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