Traneptora/FFmpeg
1
Fork 0
forked from FFmpeg/FFmpeg
Code Pull requests Activity

lavc/vvc: Fix race condition for MVs cropped to subpic

Browse source 
When the current subpicture has sps_subpic_treated_as_pic_flag equal to
1, motion vectors are cropped such that they cannot point to other
subpictures.  This was accounted for in the prediction logic, but not
in pred_get_y, which is used by the scheduling logic to determine which
parts of the reference pictures must have been reconstructed before
inter prediction of a subsequent frame may begin.  Consequently, where a
motion vector pointed to a location significantly above the current
subpicture, there was the possibility of a race condition.  Patch fixes
this by cropping the motion vector to the current subpicture in
pred_get_y.

Signed-off-by: Frank Plowman <post@frankplowman.com>
This commit is contained in:
Frank Plowman 2024-12-30 17:57:52 +00:00 • committed by Nuo Mi
parent f80af3657f
commit 539cea3183
1 changed files with 12 additions and 6 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
libavcodec/vvc/ctu.c
View file

@ -2393,13 +2393,19 @@ static int has_inter_luma(const CodingUnit *cu)
return cu->pred_mode != MODE_INTRA && cu->pred_mode != MODE_PLT && cu->tree_type != DUAL_TREE_CHROMA;
}
static int pred_get_y(const int y0, const Mv *mv, const int height)
static int pred_get_y(const VVCLocalContext *lc, const int y0, const Mv *mv, const int height)
{
return FFMAX(0, y0 + (mv->y >> 4) + height);
const VVCPPS *pps = lc->fc->ps.pps;
const int idx = lc->sc->sh.r->curr_subpic_idx;
const int top = pps->subpic_y[idx];
const int bottom = top + pps->subpic_height[idx];
return av_clip(y0 + (mv->y >> 4) + height, top, bottom);
}
static void cu_get_max_y(const CodingUnit *cu, int max_y[2][VVC_MAX_REF_ENTRIES], const VVCFrameContext *fc)
static void cu_get_max_y(const CodingUnit *cu, int max_y[2][VVC_MAX_REF_ENTRIES], const VVCLocalContext *lc)
{
const VVCFrameContext *fc = lc->fc;
const PredictionUnit *pu = &cu->pu;
if (pu->merge_gpm_flag) {
@ -2407,7 +2413,7 @@ static void cu_get_max_y(const CodingUnit *cu, int max_y[2][VVC_MAX_REF_ENTRIES]
const MvField *mvf = pu->gpm_mv + i;
const int lx = mvf->pred_flag - PF_L0;
const int idx = mvf->ref_idx[lx];
const int y = pred_get_y(cu->y0, mvf->mv + lx, cu->cb_height);
const int y = pred_get_y(lc, cu->y0, mvf->mv + lx, cu->cb_height);
max_y[lx][idx] = FFMAX(max_y[lx][idx], y);
}
@ -2425,7 +2431,7 @@ static void cu_get_max_y(const CodingUnit *cu, int max_y[2][VVC_MAX_REF_ENTRIES]
const PredFlag mask = 1 << lx;
if (mvf->pred_flag & mask) {
const int idx = mvf->ref_idx[lx];
const int y = pred_get_y(y0, mvf->mv + lx, sbh);
const int y = pred_get_y(lc, y0, mvf->mv + lx, sbh);
max_y[lx][idx] = FFMAX(max_y[lx][idx], y + max_dmvr_off);
}
@ -2452,7 +2458,7 @@ static void ctu_get_pred(VVCLocalContext *lc, const int rs)
while (cu) {
if (has_inter_luma(cu)) {
cu_get_max_y(cu, ctu->max_y, fc);
cu_get_max_y(cu, ctu->max_y, lc);
ctu->has_dmvr |= cu->pu.dmvr_flag;
}
cu = cu->next;