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lavc/hevc_refs: Fix the logic of find_ref_idx() 

Currently find_ref_idx() would trigger 2 scans in DPB to find the
requested POC:
1. Firstly, ignore MSB of ref->poc and search for the requested POC;
2. Secondly, compare the entire ref->poc with requested POC;

For long term reference, we are able to only check LSB if MSB is not
presented(e.g. delta_poc_msb_present_flag == 0). However, for short
term reference, we should never ignore poc's MSB and it should be
kind of bit-exact. (Details in 8.3.2)

Otherwise this leads to decoding failures like:
[hevc @ 0x5638f4328600] Error constructing the frame RPS.
[hevc @ 0x5638f4328600] Error parsing NAL unit #2.
[hevc @ 0x5638f4338a80] Could not find ref with POC 21
Error while decoding stream #0:0: Invalid data found when processing input

Search the requested POC based on whether MSB is used, and avoid
the 2-times scan for DPB buffer. This benefits both native HEVC
decoder and integrated HW decoders.

Signed-off-by: Xu Guangxin <guangxin.xu@intel.com>
Signed-off-by: Linjie Fu <linjie.fu@intel.com>
This commit is contained in:
Xu Guangxin 2020-05-12 21:44:21 +08:00 committed by Linjie Fu
parent 939a4db227
commit 8b5ffaea64
1 changed files with 20 additions and 18 deletions
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38
libavcodec/hevc_refs.c
View File

@ -358,24 +358,26 @@ int ff_hevc_slice_rpl(HEVCContext *s)
return 0;
}
static HEVCFrame *find_ref_idx(HEVCContext *s, int poc)
static HEVCFrame *find_ref_idx(HEVCContext *s, int poc, uint8_t use_msb)
{
int i;
int LtMask = (1 << s->ps.sps->log2_max_poc_lsb) - 1;
for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
HEVCFrame *ref = &s->DPB[i];
if (ref->frame->buf[0] && (ref->sequence == s->seq_decode)) {
if ((ref->poc & LtMask) == poc)
return ref;
if (use_msb) {
for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
HEVCFrame *ref = &s->DPB[i];
if (ref->frame->buf[0] && (ref->sequence == s->seq_decode)) {
if (ref->poc == poc)
return ref;
}
}
}
for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
HEVCFrame *ref = &s->DPB[i];
if (ref->frame->buf[0] && ref->sequence == s->seq_decode) {
if (ref->poc == poc || (ref->poc & LtMask) == poc)
return ref;
} else {
int LtMask = (1 << s->ps.sps->log2_max_poc_lsb) - 1;
for (i = 0; i < FF_ARRAY_ELEMS(s->DPB); i++) {
HEVCFrame *ref = &s->DPB[i];
if (ref->frame->buf[0] && ref->sequence == s->seq_decode) {
if ((ref->poc & LtMask) == poc)
return ref;
}
}
}
@ -427,9 +429,9 @@ static HEVCFrame *generate_missing_ref(HEVCContext *s, int poc)
/* add a reference with the given poc to the list and mark it as used in DPB */
static int add_candidate_ref(HEVCContext *s, RefPicList *list,
int poc, int ref_flag)
int poc, int ref_flag, uint8_t use_msb)
{
HEVCFrame *ref = find_ref_idx(s, poc);
HEVCFrame *ref = find_ref_idx(s, poc, use_msb);
if (ref == s->ref || list->nb_refs >= HEVC_MAX_REFS)
return AVERROR_INVALIDDATA;
@ -485,7 +487,7 @@ int ff_hevc_frame_rps(HEVCContext *s)
else
list = ST_CURR_AFT;
ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_SHORT_REF);
ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_SHORT_REF, 1);
if (ret < 0)
goto fail;
}
@ -495,7 +497,7 @@ int ff_hevc_frame_rps(HEVCContext *s)
int poc = long_rps->poc[i];
int list = long_rps->used[i] ? LT_CURR : LT_FOLL;
ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_LONG_REF);
ret = add_candidate_ref(s, &rps[list], poc, HEVC_FRAME_FLAG_LONG_REF, long_rps->poc_msb_present[i]);
if (ret < 0)
goto fail;
}