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Code Issues Releases Activity

fix idct permutation

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Originally committed as revision 4258 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2005-05-17 11:31:57 +00:00
parent 8b6103da0f
commit 36af0c959e
1 changed files with 12 additions and 6 deletions
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18
libavcodec/vp3.c
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@ -250,6 +250,8 @@ typedef struct Vp3DecodeContext {
int u_fragment_start;
int v_fragment_start;
ScanTable scantable;
/* tables */
uint16_t coded_dc_scale_factor[64];
uint32_t coded_ac_scale_factor[64];
@ -885,20 +887,21 @@ static void init_dequantizer(Vp3DecodeContext *s)
/* scale AC quantizers, zigzag at the same time in preparation for
* the dequantization phase */
for (i = 1; i < 64; i++) {
int k= s->scantable.scantable[i];
j = s->scantable.permutated[i];
j = i;
s->intra_y_dequant[j] = s->coded_intra_y_dequant[i] * ac_scale_factor / 100;
s->intra_y_dequant[j] = s->coded_intra_y_dequant[k] * ac_scale_factor / 100;
if (s->intra_y_dequant[j] < MIN_DEQUANT_VAL)
s->intra_y_dequant[j] = MIN_DEQUANT_VAL;
s->intra_y_dequant[j] *= SCALER;
s->intra_c_dequant[j] = s->coded_intra_c_dequant[i] * ac_scale_factor / 100;
s->intra_c_dequant[j] = s->coded_intra_c_dequant[k] * ac_scale_factor / 100;
if (s->intra_c_dequant[j] < MIN_DEQUANT_VAL)
s->intra_c_dequant[j] = MIN_DEQUANT_VAL;
s->intra_c_dequant[j] *= SCALER;
s->inter_dequant[j] = s->coded_inter_dequant[i] * ac_scale_factor / 100;
s->inter_dequant[j] = s->coded_inter_dequant[k] * ac_scale_factor / 100;
if (s->inter_dequant[j] < MIN_DEQUANT_VAL * 2)
s->inter_dequant[j] = MIN_DEQUANT_VAL * 2;
s->inter_dequant[j] *= SCALER;
@ -1633,6 +1636,7 @@ static int unpack_vlcs(Vp3DecodeContext *s, GetBitContext *gb,
int zero_run;
DCTELEM coeff;
Vp3Fragment *fragment;
uint8_t *perm= s->scantable.permutated;
if ((first_fragment >= s->fragment_count) ||
(last_fragment >= s->fragment_count)) {
@ -1659,7 +1663,7 @@ static int unpack_vlcs(Vp3DecodeContext *s, GetBitContext *gb,
if (!eob_run) {
fragment->coeff_count += zero_run;
if (fragment->coeff_count < 64)
fragment->coeffs[dezigzag_index[fragment->coeff_count++]] = coeff;
fragment->coeffs[perm[fragment->coeff_count++]] = coeff;
debug_vlc(" fragment %d coeff = %d\n",
s->coded_fragment_list[i], fragment->coeffs[coeff_index]);
} else {
@ -2510,6 +2514,8 @@ static int vp3_decode_init(AVCodecContext *avctx)
if(avctx->idct_algo==FF_IDCT_AUTO)
avctx->idct_algo=FF_IDCT_VP3;
dsputil_init(&s->dsp, avctx);
ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);
/* initialize to an impossible value which will force a recalculation
* in the first frame decode */