On 02/29/2012 03:12 AM, Ronald S. Bultje wrote:
From: "Ronald S. Bultje"<[email protected]>
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: [email protected]
---
libavcodec/dca.c | 31 ++++++++++++++++++++++---------
libavcodec/dcadata.h | 2 +-
2 files changed, 23 insertions(+), 10 deletions(-)
diff --git a/libavcodec/dca.c b/libavcodec/dca.c
index 3f62c1e..381087a 100644
--- a/libavcodec/dca.c
+++ b/libavcodec/dca.c
@@ -718,15 +718,18 @@ static int dca_subframe_header(DCAContext *s, int
base_channel, int block_index)
for (j = base_channel; j< s->prim_channels; j++) {
const uint32_t *scale_table;
- int scale_sum;
+ int scale_sum, log_size;
memset(s->scale_factor[j], 0,
s->subband_activity[j] * sizeof(s->scale_factor[0][0][0]) * 2);
- if (s->scalefactor_huffman[j] == 6)
+ if (s->scalefactor_huffman[j] == 6) {
scale_table = scale_factor_quant7;
- else
+ log_size = 7;
+ } else {
scale_table = scale_factor_quant6;
+ log_size = 6;
+ }
/* When huffman coded, only the difference is encoded */
scale_sum = 0;
@@ -734,13 +737,13 @@ static int dca_subframe_header(DCAContext *s, int
base_channel, int block_index)
for (k = 0; k< s->subband_activity[j]; k++) {
if (k>= s->vq_start_subband[j] || s->bitalloc[j][k]> 0) {
scale_sum = get_scale(&s->gb, s->scalefactor_huffman[j],
scale_sum);
- s->scale_factor[j][k][0] = scale_table[scale_sum];
+ s->scale_factor[j][k][0] =
scale_table[av_clip_uintp2(scale_sum, log_size)];
}
if (k< s->vq_start_subband[j]&& s->transition_mode[j][k]) {
/* Get second scale factor */
scale_sum = get_scale(&s->gb, s->scalefactor_huffman[j],
scale_sum);
- s->scale_factor[j][k][1] = scale_table[scale_sum];
+ s->scale_factor[j][k][1] =
scale_table[av_clip_uintp2(scale_sum, log_size)];
}
}
}
Move this check to get_scale() instead of duplicating it.
@@ -790,9 +793,17 @@ static int dca_subframe_header(DCAContext *s, int
base_channel, int block_index)
}
} else {
int am = s->amode& DCA_CHANNEL_MASK;
- for (j = base_channel; j< s->prim_channels; j++) {
- s->downmix_coef[j][0] = dca_default_coeffs[am][j][0];
- s->downmix_coef[j][1] = dca_default_coeffs[am][j][1];
+ if (am< FF_ARRAY_ELEMS(dca_default_coeffs)) {
+ for (j = base_channel; j< s->prim_channels; j++) {
+ s->downmix_coef[j][0] = dca_default_coeffs[am][j][0];
+ s->downmix_coef[j][1] = dca_default_coeffs[am][j][1];
+ }
+ } else {
+ av_log_missing_feature(s->avctx, "non-standard channel mask
value", 1);
+ for (j = base_channel; j< s->prim_channels; j++) {
+ s->downmix_coef[j][0] = 0;
+ s->downmix_coef[j][1] = 0;
+ }
}
}
}
This needs to be checked against the spec. I don't think this is a
missing feature. Just broken bitstream. And in that case just making
sure am is less then 10 should be enough.
@@ -822,6 +833,7 @@ static int dca_subframe_header(DCAContext *s, int
base_channel, int block_index)
int lfe_samples = 2 * s->lfe * (4 + block_index);
int lfe_end_sample = 2 * s->lfe * (4 + block_index +
s->subsubframes[s->current_subframe]);
float lfe_scale;
+ int idx;
for (j = lfe_samples; j< lfe_end_sample; j++) {
/* Signed 8 bits int */
@@ -829,7 +841,8 @@ static int dca_subframe_header(DCAContext *s, int
base_channel, int block_index)
}
/* Scale factor index */
- s->lfe_scale_factor = scale_factor_quant7[get_bits(&s->gb, 8)];
+ idx = get_bits(&s->gb, 8);
+ s->lfe_scale_factor = scale_factor_quant7[FFMIN(idx, 127)];
The table is 128 elements big. So skip 1 bit instead.
-static const uint8_t dca_default_coeffs[16][5][2] = {
+static const uint8_t dca_default_coeffs[10][5][2] = {
{ { 13, 13 }, },
{ { 0, 64 }, { 64, 0 }, },
{ { 0, 64 }, { 64, 0 }, },
OK
MvH
Benjamin Larsson
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