>From: ffmpeg-devel <ffmpeg-devel-boun...@ffmpeg.org> On Behalf Of James >Almer >Sent: Friday, March 29, 2024 8:46 PM >To: ffmpeg-devel@ffmpeg.org >Subject: Re: [FFmpeg-devel] [PATCH] avcodec/hevc_ps: fix the problem of >memcmp losing effectiveness > >On 3/28/2024 10:15 AM, tong1.wu-at-intel....@ffmpeg.org wrote: >> From: Tong Wu <tong1...@intel.com> >> >> HEVCHdrParams* receives a pointer which points to a dynamically >> allocated memory block. It causes the memcmp always returning 1. >> Add a function to do the comparision. A condition is also added to >> avoid malloc(0). >> >> Signed-off-by: Tong Wu <tong1...@intel.com> >> --- >> libavcodec/hevc_ps.c | 20 ++++++++++++++++---- >> libavcodec/hevc_ps.h | 4 +++- >> 2 files changed, 19 insertions(+), 5 deletions(-) >> >> diff --git a/libavcodec/hevc_ps.c b/libavcodec/hevc_ps.c >> index cbef3ef4cd..8b3a27a17c 100644 >> --- a/libavcodec/hevc_ps.c >> +++ b/libavcodec/hevc_ps.c >> @@ -449,6 +449,16 @@ static void uninit_vps(FFRefStructOpaque opaque, >void *obj) >> av_freep(&vps->hdr); >> } >> >> +static int compare_vps(const HEVCVPS *vps1, const HEVCVPS *vps2) >> +{ >> + if ((!vps1->hdr && !vps2->hdr) || >> + (vps1->hdr && vps2->hdr && !memcmp(vps1->hdr, vps2->hdr, >sizeof(*vps1->hdr)))) { > >I think this should be vps1->vps_num_hrd_parameters * >sizeof(*vps1->hdr), and done after the memcmp below to ensure >vps_num_hrd_parameters is the same value in both structs.
Updated as suggested. Thanks. Tong > >> + return !memcmp(vps1, vps2, offsetof(HEVCVPS, hdr)); >> + } >> + >> + return 0; >> +} >> + >> int ff_hevc_decode_nal_vps(GetBitContext *gb, AVCodecContext *avctx, >> HEVCParamSets *ps) >> { >> @@ -545,9 +555,11 @@ int ff_hevc_decode_nal_vps(GetBitContext *gb, >AVCodecContext *avctx, >> goto err; >> } >> >> - vps->hdr = av_calloc(vps->vps_num_hrd_parameters, sizeof(*vps- >>hdr)); >> - if (!vps->hdr) >> - goto err; >> + if (vps->vps_num_hrd_parameters) { >> + vps->hdr = av_calloc(vps->vps_num_hrd_parameters, sizeof(*vps- >>hdr)); >> + if (!vps->hdr) >> + goto err; >> + } >> >> for (i = 0; i < vps->vps_num_hrd_parameters; i++) { >> int common_inf_present = 1; >> @@ -569,7 +581,7 @@ int ff_hevc_decode_nal_vps(GetBitContext *gb, >AVCodecContext *avctx, >> } >> >> if (ps->vps_list[vps_id] && >> - !memcmp(ps->vps_list[vps_id], vps, sizeof(*vps))) { >> + compare_vps(ps->vps_list[vps_id], vps)) { >> ff_refstruct_unref(&vps); >> } else { >> remove_vps(ps, vps_id); >> diff --git a/libavcodec/hevc_ps.h b/libavcodec/hevc_ps.h >> index cc75aeb8d3..0d8eaf2b3e 100644 >> --- a/libavcodec/hevc_ps.h >> +++ b/libavcodec/hevc_ps.h >> @@ -153,7 +153,6 @@ typedef struct PTL { >> >> typedef struct HEVCVPS { >> unsigned int vps_id; >> - HEVCHdrParams *hdr; >> >> uint8_t vps_temporal_id_nesting_flag; >> int vps_max_layers; >> @@ -175,6 +174,9 @@ typedef struct HEVCVPS { >> >> uint8_t data[4096]; >> int data_size; >> + /* Put this at the end of the structure to make it easier to calculate >> the >> + * size before this pointer, which is used for memcmp */ >> + HEVCHdrParams *hdr; >> } HEVCVPS; >> >> typedef struct ScalingList { >_______________________________________________ >ffmpeg-devel mailing list >ffmpeg-devel@ffmpeg.org >https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > >To unsubscribe, visit link above, or email >ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".