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WMA: store level_table as floats, use type punning for sign flip in decode

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Originally committed as revision 20078 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Måns Rullgård
2009-09-29 10:38:34 +00:00
parent ff00b94e9d
commit 076a9dea1e
4 changed files with 18 additions and 11 deletions
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19
libavcodec/wma.c
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@ -29,7 +29,7 @@
/* XXX: use same run/length optimization as mpeg decoders */
//FIXME maybe split decode / encode or pass flag
static void init_coef_vlc(VLC *vlc, uint16_t **prun_table,
uint16_t **plevel_table, uint16_t **pint_table,
float **plevel_table, uint16_t **pint_table,
const CoefVLCTable *vlc_table)
{
int n = vlc_table->n;
@ -37,12 +37,14 @@ static void init_coef_vlc(VLC *vlc, uint16_t **prun_table,
const uint32_t *table_codes = vlc_table->huffcodes;
const uint16_t *levels_table = vlc_table->levels;
uint16_t *run_table, *level_table, *int_table;
float *flevel_table;
int i, l, j, k, level;
init_vlc(vlc, VLCBITS, n, table_bits, 1, 1, table_codes, 4, 4, 0);
run_table = av_malloc(n * sizeof(uint16_t));
level_table = av_malloc(n * sizeof(uint16_t));
flevel_table= av_malloc(n * sizeof(*flevel_table));
int_table = av_malloc(n * sizeof(uint16_t));
i = 2;
level = 1;
@ -53,13 +55,15 @@ static void init_coef_vlc(VLC *vlc, uint16_t **prun_table,
for (j = 0; j < l; j++) {
run_table[i] = j;
level_table[i] = level;
flevel_table[i]= level;
i++;
}
level++;
}
*prun_table = run_table;
*plevel_table = level_table;
*plevel_table = flevel_table;
*pint_table = int_table;
av_free(level_table);
}
/**
@ -465,19 +469,22 @@ unsigned int ff_wma_get_large_val(GetBitContext* gb)
*/
int ff_wma_run_level_decode(AVCodecContext* avctx, GetBitContext* gb,
VLC *vlc,
const uint16_t *level_table, const uint16_t *run_table,
const float *level_table, const uint16_t *run_table,
int version, WMACoef *ptr, int offset,
int num_coefs, int block_len, int frame_len_bits,
int coef_nb_bits)
{
int code, level, sign;
const uint32_t *ilvl = (const uint32_t*)level_table;
uint32_t *iptr = (uint32_t*)ptr;
const unsigned int coef_mask = block_len - 1;
for (; offset < num_coefs; offset++) {
code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);
if (code > 1) {
/** normal code */
offset += run_table[code];
level = level_table[code];
sign = get_bits1(gb) - 1;
iptr[offset & coef_mask] = ilvl[code] ^ sign<<31;
} else if (code == 1) {
/** EOB */
break;
@ -503,9 +510,9 @@ int ff_wma_run_level_decode(AVCodecContext* avctx, GetBitContext* gb,
offset += get_bits(gb, 2) + 1;
}
}
sign = get_bits1(gb) - 1;
ptr[offset & coef_mask] = (level^sign) - sign;
}
sign = get_bits1(gb) - 1;
ptr[offset & coef_mask] = (level^sign) - sign;
}
/** NOTE: EOB can be omitted */
if (offset > num_coefs) {