lavc/hevc_ps: reduce the size of used_by_curr_pic_lt_sps_flag

It is currently an array of 32 uint8_t, each storing a single flag. A
single uint32_t is sufficient.

libavcodec/hevc_ps.c

@@ -1094,9 +1094,11 @@ int ff_hevc_parse_sps(HEVCSPS *sps, GetBitContext *gb, unsigned int *sps_id,
                    sps->num_long_term_ref_pics_sps);
             return AVERROR_INVALIDDATA;
         }
+
+        sps->used_by_curr_pic_lt = 0;
         for (i = 0; i < sps->num_long_term_ref_pics_sps; i++) {
             sps->lt_ref_pic_poc_lsb_sps[i]       = get_bits(gb, sps->log2_max_poc_lsb);
-            sps->used_by_curr_pic_lt_sps_flag[i] = get_bits1(gb);
+            sps->used_by_curr_pic_lt            |= get_bits1(gb) * (1 << i);
         }
     }
 

libavcodec/hevc_ps.h

@@ -230,7 +230,7 @@ typedef struct HEVCSPS {
 
     uint8_t long_term_ref_pics_present_flag;
     uint16_t lt_ref_pic_poc_lsb_sps[HEVC_MAX_LONG_TERM_REF_PICS];
-    uint8_t used_by_curr_pic_lt_sps_flag[HEVC_MAX_LONG_TERM_REF_PICS];
+    uint32_t used_by_curr_pic_lt;
     uint8_t num_long_term_ref_pics_sps;
 
     struct {

libavcodec/hevcdec.c

@@ -295,7 +295,7 @@ static int decode_lt_rps(HEVCContext *s, LongTermRPS *rps, GetBitContext *gb)
                 lt_idx_sps = get_bits(gb, av_ceil_log2(sps->num_long_term_ref_pics_sps));
 
             rps->poc[i]  = sps->lt_ref_pic_poc_lsb_sps[lt_idx_sps];
-            rps->used[i] = sps->used_by_curr_pic_lt_sps_flag[lt_idx_sps];
+            rps->used[i] = !!(sps->used_by_curr_pic_lt & (1 << lt_idx_sps));
         } else {
             rps->poc[i]  = get_bits(gb, sps->log2_max_poc_lsb);
             rps->used[i] = get_bits1(gb);

libavcodec/vulkan_hevc.c

@@ -386,11 +386,10 @@ static void set_sps(const HEVCSPS *sps, int sps_idx,
     }
 
     *ltr = (StdVideoH265LongTermRefPicsSps) {
-        .used_by_curr_pic_lt_sps_flag = 0x0,
+        .used_by_curr_pic_lt_sps_flag = sps->used_by_curr_pic_lt,
     };
 
     for (int i = 0; i < sps->num_long_term_ref_pics_sps; i++) {
-        ltr->used_by_curr_pic_lt_sps_flag |= sps->used_by_curr_pic_lt_sps_flag[i] << i;
         ltr->lt_ref_pic_poc_lsb_sps[i]     = sps->lt_ref_pic_poc_lsb_sps[i];
     }