On 1/27/2024 9:05 PM, Michael Niedermayer wrote:
On Sat, Jan 27, 2024 at 09:02:30PM -0300, James Almer wrote:
On 1/27/2024 8:56 PM, Michael Niedermayer wrote:
On Sat, Jan 27, 2024 at 09:25:16AM -0300, James Almer wrote:
On 1/26/2024 6:46 PM, Michael Niedermayer wrote:
It is not possible to encode a index into an empty list. Thus
this must be invalid at this point or before.
Its likely a broader earlier check can be used here, someone knowing
VVC should look at that. Its not immedeatly obvious from the spec
by looking for numlayerolss
Can you check if the following fixes it?
diff --git a/libavcodec/cbs_h266_syntax_template.c
b/libavcodec/cbs_h266_syntax_template.c
index 549d021211..40572dadb5 100644
--- a/libavcodec/cbs_h266_syntax_template.c
+++ b/libavcodec/cbs_h266_syntax_template.c
@@ -793,6 +793,7 @@ static int FUNC(vps) (CodedBitstreamContext *ctx, RWContext
*rw,
{
//calc NumMultiLayerOlss
int m;
+ int num_layers_in_ols = 0;
uint8_t dependency_flag[VVC_MAX_LAYERS][VVC_MAX_LAYERS];
uint16_t num_output_layers_in_ols[VVC_MAX_TOTAL_NUM_OLSS];
uint8_t
num_sub_layers_in_layer_in_ols[VVC_MAX_TOTAL_NUM_OLSS][VVC_MAX_TOTAL_NUM_OLSS];
@@ -895,7 +896,6 @@ static int FUNC(vps) (CodedBitstreamContext *ctx, RWContext
*rw,
return AVERROR_INVALIDDATA;
}
for (i = 1; i < total_num_olss; i++) {
- int num_layers_in_ols = 0;
if (current->vps_each_layer_is_an_ols_flag) {
num_layers_in_ols = 1;
} else if (current->vps_ols_mode_idc == 0 ||
num_layers_in_ols is not meant to be reset on every loop.
replacing my patch by yours does not change
num_multi_layer_olss from being 0
and if its 0 then "num_multi_layer_olss - 1" causes problems as a limit
more precissely this:
i can also send you the file if you want?
No, this should be looked at by someone more familiar with VVC.
ive already sent the fuzzer samples to nuomi and frank plowman
And my patch should be applied either way. The current code is wrong.
I did not suggest not to do that :)
Well, turns out the current code is fine and my suggested change above
is wrong. Fun how that goes.
Can you test the following instead?
diff --git a/libavcodec/cbs_h266_syntax_template.c
b/libavcodec/cbs_h266_syntax_template.c
index 549d021211..30b4ae3bc0 100644
--- a/libavcodec/cbs_h266_syntax_template.c
+++ b/libavcodec/cbs_h266_syntax_template.c
@@ -764,7 +764,7 @@ static int FUNC(vps) (CodedBitstreamContext *ctx, RWContext
*rw,
infer(vps_each_layer_is_an_ols_flag, 0);
if (!current->vps_each_layer_is_an_ols_flag) {
if (!current->vps_all_independent_layers_flag)
- ub(2, vps_ols_mode_idc);
+ u(2, vps_ols_mode_idc, 0, 2);
else
infer(vps_ols_mode_idc, 2);
if (current->vps_ols_mode_idc == 2) {
@@ -902,11 +902,10 @@ static int FUNC(vps) (CodedBitstreamContext *ctx,
RWContext *rw,
current->vps_ols_mode_idc == 1) {
num_layers_in_ols = i + 1;
} else if (current->vps_ols_mode_idc == 2) {
- for (k = 0, j = 0; k <= current->vps_max_layers_minus1; k++) {
+ for (k = 0, j = 0; k <= current->vps_max_layers_minus1; k++)
if (layer_included_in_ols_flag[i][k])
j++;
- num_layers_in_ols = j;
- }
+ num_layers_in_ols = j;
}
if (num_layers_in_ols > 1) {
num_multi_layer_olss++;
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