static uint8_t huffman_2step_pair(uint8_t cb, bitfile *ld, int16_t *sp)
{
uint32_t cw;
uint16_t offset = 0;
uint8_t extra_bits;
cw = faad_showbits(ld, hcbN[cb]);
offset = hcb_table[cb][cw].offset;
extra_bits = hcb_table[cb][cw].extra_bits;
if (extra_bits)
{
/* we know for sure it's more than hcbN[cb] bits long */
faad_flushbits(ld, hcbN[cb]);
offset += (uint16_t)faad_showbits(ld, extra_bits);
faad_flushbits(ld, hcb_2_pair_table[cb][offset].bits - hcbN[cb]);
} else {
faad_flushbits(ld, hcb_2_pair_table[cb][offset].bits);
}
if (offset > hcb_2_pair_table_size[cb])
{
/* printf("ERROR: offset into hcb_2_pair_table = %d >%d!\n", offset,
hcb_2_pair_table_size[cb]); */
return 10;
}
sp[0] = hcb_2_pair_table[cb][offset].x;
sp[1] = hcb_2_pair_table[cb][offset].y;
return 0;
}
/*
* adts_header
*/
int get_adts_header(faacDecHandle hDecoder)
{
int sync = 0;
ADTS_Header *p = &hDecoder->adts_header;
faad_byte_align(&hDecoder->ld);
sync = faad_showbits(&hDecoder->ld, 12);
while (sync != 4096 - 1) {
faad_flushbits(&hDecoder->ld, 8);
if (faad_bits_done(&hDecoder->ld) != 0) {
return -1;
}
sync = faad_showbits(&hDecoder->ld, 12);
}
faad_flushbits(&hDecoder->ld, 12);
if (hDecoder->frameNum) {
faad_getbits(&hDecoder->ld, 16);
#if 0
if (p->fixed.ID == 0) /* MPEG2 AAC doesn't have this */
faad_getbits(&hDecoder->ld, 2);
#endif
} else {
/* Syncword found, proceed to read in the fixed ADTS header */
p->fixed.ID = faad_get1bit(&hDecoder->ld); /* 0 -> MPEG4, 1 -> MPEG2 */
hDecoder->isMpeg4 = !p->fixed.ID;
p->fixed.layer = faad_getbits(&hDecoder->ld, 2);
p->fixed.protection_absent = faad_get1bit(&hDecoder->ld);
hDecoder->mc_info.object_type = p->fixed.object_type = faad_getbits(&hDecoder->ld, 2);
hDecoder->mc_info.sampling_rate_idx = p->fixed.sampling_rate_idx = faad_getbits(&hDecoder->ld, 4);
p->fixed.private_bit = faad_get1bit(&hDecoder->ld);
p->fixed.channel_configuration = faad_getbits(&hDecoder->ld, 3);
p->fixed.original_copy = faad_get1bit(&hDecoder->ld);
p->fixed.home = faad_get1bit(&hDecoder->ld);
#if 0
if (p->fixed.ID == 0) /* MPEG2 AAC doesn't have this */
p->fixed.emphasis = faad_getbits(&hDecoder->ld, 2);
#endif
}
/* ...and the variable ADTS header */
p->variable.copy_id_bit = faad_get1bit(&hDecoder->ld);
p->variable.copy_id_start = faad_get1bit(&hDecoder->ld);
p->variable.frame_length = faad_getbits(&hDecoder->ld, 13);
p->variable.buffer_fullness = faad_getbits(&hDecoder->ld, 11);
p->variable.raw_blocks = faad_getbits(&hDecoder->ld, 2);
/* ADTS error check (ignored) */
if(!p->fixed.protection_absent)
faad_getbits(&hDecoder->ld, 16);
return 0;
}
/* return next n bits (right adjusted) */
uint32_t faad_getbits(bitfile *ld, int n)
{
long l;
l = faad_showbits(ld, n);
faad_flushbits(ld, n);
return l;
}
uint32_t faad_byte_align(bitfile *ld)
{
int i;
if (ld->bitcnt == 0) return 0;
i = 8 - ld->bitcnt;
faad_flushbits(ld, i);
return i;
}
uint8_t faad_byte_align(bitfile *ld)
{
int remainder = (32 - ld->bits_left) & 0x7;
if (remainder)
{
faad_flushbits(ld, 8 - remainder);
return (uint8_t)(8 - remainder);
}
return 0;
}
