[FFmpeg-cvslog] h264: don't touch H264Context->ref_count[] during MB decoding
Ronald S. Bultje
git at videolan.org
Fri Oct 5 17:08:43 CEST 2012
ffmpeg | branch: master | Ronald S. Bultje <rsbultje at gmail.com> | Wed Oct 3 16:25:14 2012 -0700| [f6f7d1504134683c435e2c7d804279d982e52bb4] | committer: Luca Barbato
h264: don't touch H264Context->ref_count[] during MB decoding
The variable is copied to subsequent threads at the same time, so this
may cause wrong ref_count[] values to be copied to subsequent threads.
This bug was found using TSAN.
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f6f7d1504134683c435e2c7d804279d982e52bb4
---
libavcodec/h264_cabac.c | 41 ++++++++++++++++-------------------------
libavcodec/h264_cavlc.c | 33 +++++++++++++--------------------
2 files changed, 29 insertions(+), 45 deletions(-)
diff --git a/libavcodec/h264_cabac.c b/libavcodec/h264_cabac.c
index f2fea5d..92c1c03 100644
--- a/libavcodec/h264_cabac.c
+++ b/libavcodec/h264_cabac.c
@@ -2005,11 +2005,6 @@ decode_intra_mb:
return 0;
}
- if(MB_MBAFF){
- h->ref_count[0] <<= 1;
- h->ref_count[1] <<= 1;
- }
-
fill_decode_caches(h, mb_type);
if( IS_INTRA( mb_type ) ) {
@@ -2078,10 +2073,11 @@ decode_intra_mb:
for( i = 0; i < 4; i++ ) {
if(IS_DIRECT(h->sub_mb_type[i])) continue;
if(IS_DIR(h->sub_mb_type[i], 0, list)){
- if( h->ref_count[list] > 1 ){
+ int rc = h->ref_count[list] << MB_MBAFF;
+ if (rc > 1) {
ref[list][i] = decode_cabac_mb_ref( h, list, 4*i );
- if(ref[list][i] >= (unsigned)h->ref_count[list]){
- av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref[list][i], h->ref_count[list]);
+ if (ref[list][i] >= (unsigned) rc) {
+ av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref[list][i], rc);
return -1;
}
}else
@@ -2163,11 +2159,11 @@ decode_intra_mb:
if(IS_16X16(mb_type)){
for(list=0; list<h->list_count; list++){
if(IS_DIR(mb_type, 0, list)){
- int ref;
- if(h->ref_count[list] > 1){
+ int ref, rc = h->ref_count[list] << MB_MBAFF;
+ if (rc > 1) {
ref= decode_cabac_mb_ref(h, list, 0);
- if(ref >= (unsigned)h->ref_count[list]){
- av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref, h->ref_count[list]);
+ if (ref >= (unsigned) rc) {
+ av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref, rc);
return -1;
}
}else
@@ -2191,11 +2187,11 @@ decode_intra_mb:
for(list=0; list<h->list_count; list++){
for(i=0; i<2; i++){
if(IS_DIR(mb_type, i, list)){
- int ref;
- if(h->ref_count[list] > 1){
+ int ref, rc = h->ref_count[list] << MB_MBAFF;
+ if (rc > 1) {
ref= decode_cabac_mb_ref( h, list, 8*i );
- if(ref >= (unsigned)h->ref_count[list]){
- av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref, h->ref_count[list]);
+ if (ref >= (unsigned) rc) {
+ av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref, rc);
return -1;
}
}else
@@ -2226,11 +2222,11 @@ decode_intra_mb:
for(list=0; list<h->list_count; list++){
for(i=0; i<2; i++){
if(IS_DIR(mb_type, i, list)){ //FIXME optimize
- int ref;
- if(h->ref_count[list] > 1){
+ int ref, rc = h->ref_count[list] << MB_MBAFF;
+ if (rc > 1) {
ref= decode_cabac_mb_ref( h, list, 4*i );
- if(ref >= (unsigned)h->ref_count[list]){
- av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref, h->ref_count[list]);
+ if (ref >= (unsigned) rc) {
+ av_log(s->avctx, AV_LOG_ERROR, "Reference %d >= %d\n", ref, rc);
return -1;
}
}else
@@ -2403,10 +2399,5 @@ decode_intra_mb:
s->current_picture.f.qscale_table[mb_xy] = s->qscale;
write_back_non_zero_count(h);
- if(MB_MBAFF){
- h->ref_count[0] >>= 1;
- h->ref_count[1] >>= 1;
- }
-
return 0;
}
diff --git a/libavcodec/h264_cavlc.c b/libavcodec/h264_cavlc.c
index c4159e2..8996057 100644
--- a/libavcodec/h264_cavlc.c
+++ b/libavcodec/h264_cavlc.c
@@ -784,11 +784,6 @@ decode_intra_mb:
return 0;
}
- if(MB_MBAFF){
- h->ref_count[0] <<= 1;
- h->ref_count[1] <<= 1;
- }
-
fill_decode_neighbors(h, mb_type);
fill_decode_caches(h, mb_type);
@@ -868,7 +863,7 @@ decode_intra_mb:
}
for(list=0; list<h->list_count; list++){
- int ref_count= IS_REF0(mb_type) ? 1 : h->ref_count[list];
+ int ref_count = IS_REF0(mb_type) ? 1 : h->ref_count[list] << MB_MBAFF;
for(i=0; i<4; i++){
if(IS_DIRECT(h->sub_mb_type[i])) continue;
if(IS_DIR(h->sub_mb_type[i], 0, list)){
@@ -948,13 +943,14 @@ decode_intra_mb:
for(list=0; list<h->list_count; list++){
unsigned int val;
if(IS_DIR(mb_type, 0, list)){
- if(h->ref_count[list]==1){
+ int rc = h->ref_count[list] << MB_MBAFF;
+ if (rc == 1) {
val= 0;
- }else if(h->ref_count[list]==2){
+ } else if (rc == 2) {
val= get_bits1(&s->gb)^1;
}else{
val= get_ue_golomb_31(&s->gb);
- if(val >= h->ref_count[list]){
+ if (val >= rc) {
av_log(h->s.avctx, AV_LOG_ERROR, "ref %u overflow\n", val);
return -1;
}
@@ -978,13 +974,14 @@ decode_intra_mb:
for(i=0; i<2; i++){
unsigned int val;
if(IS_DIR(mb_type, i, list)){
- if(h->ref_count[list] == 1){
+ int rc = h->ref_count[list] << MB_MBAFF;
+ if (rc == 1) {
val= 0;
- }else if(h->ref_count[list] == 2){
+ } else if (rc == 2) {
val= get_bits1(&s->gb)^1;
}else{
val= get_ue_golomb_31(&s->gb);
- if(val >= h->ref_count[list]){
+ if (val >= rc) {
av_log(h->s.avctx, AV_LOG_ERROR, "ref %u overflow\n", val);
return -1;
}
@@ -1015,13 +1012,14 @@ decode_intra_mb:
for(i=0; i<2; i++){
unsigned int val;
if(IS_DIR(mb_type, i, list)){ //FIXME optimize
- if(h->ref_count[list]==1){
+ int rc = h->ref_count[list] << MB_MBAFF;
+ if (rc == 1) {
val= 0;
- }else if(h->ref_count[list]==2){
+ } else if (rc == 2) {
val= get_bits1(&s->gb)^1;
}else{
val= get_ue_golomb_31(&s->gb);
- if(val >= h->ref_count[list]){
+ if (val >= rc) {
av_log(h->s.avctx, AV_LOG_ERROR, "ref %u overflow\n", val);
return -1;
}
@@ -1180,10 +1178,5 @@ decode_intra_mb:
s->current_picture.f.qscale_table[mb_xy] = s->qscale;
write_back_non_zero_count(h);
- if(MB_MBAFF){
- h->ref_count[0] >>= 1;
- h->ref_count[1] >>= 1;
- }
-
return 0;
}
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