h265parser/bitwriter: add some comments for ceil_log2 use

Validate that the length of field must be calculate with
ceil_logs2 and not bit storage.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7905>

diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265bitwriter.c b/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265bitwriter.c
index 8cd5c741f0bdd8ee9d66b2c1b4be363231020606..5221a4ffc794f027f9f91aa3bed396d7479aed5b 100644 (file)
--- a/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265bitwriter.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265bitwriter.c
@@ -1437,6 +1437,7 @@ _h265_slice_bit_writer_ref_pic_list_modification (const GstH265SliceHdr *
 
   if (rpl_mod->ref_pic_list_modification_flag_l0) {
     for (i = 0; i <= slice->num_ref_idx_l0_active_minus1; i++) {
+      /* 7.4.7.2 list_entry_l0 */
       WRITE_BITS (bw, rpl_mod->list_entry_l0[i], n);
     }
   }
@@ -1575,7 +1576,7 @@ _h265_bit_writer_slice_header (const GstH265SliceHdr * slice,
 
     if (slice->pps->dependent_slice_segments_enabled_flag)
       WRITE_BITS (bw, slice->dependent_slice_segment_flag, 1);
-    /* sice_segment_address parsing */
+    /* 7.4.7.1 slice_segment_address parsing */
     WRITE_BITS (bw, slice->segment_address, n);
   }
 
@@ -1610,6 +1611,7 @@ _h265_bit_writer_slice_header (const GstH265SliceHdr * slice,
             sps->num_short_term_ref_pic_sets - 1)
           goto error;
 
+        /*  7.4.7.1 short_term_ref_pic_set_idx */
         WRITE_BITS (bw, slice->short_term_ref_pic_set_idx, n);
       }
 
@@ -1625,6 +1627,7 @@ _h265_bit_writer_slice_header (const GstH265SliceHdr * slice,
         for (i = 0; i < limit; i++) {
           if (i < slice->num_long_term_sps) {
             if (sps->num_long_term_ref_pics_sps > 1) {
+              /* 7.4.7.1 lt_idx_sps */
               const guint n =
                   gst_util_ceil_log2 (sps->num_long_term_ref_pics_sps);
               WRITE_BITS (bw, slice->lt_idx_sps[i], n);

diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265parser.c b/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265parser.c
index 9d126080f218646ef45dc21697572efd49f66ca8..f554de5a5838506fd9dc5bfa65f083308bb4d432 100644 (file)
--- a/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265parser.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth265parser.c
@@ -926,6 +926,7 @@ gst_h265_slice_parse_ref_pic_list_modification (GstH265SliceHdr * slice,
 
   if (rpl_mod->ref_pic_list_modification_flag_l0) {
     for (i = 0; i <= slice->num_ref_idx_l0_active_minus1; i++) {
+      /* 7.4.7.2 list_entry_l0 */
       READ_UINT32 (nr, rpl_mod->list_entry_l0[i], n);
       CHECK_ALLOWED_MAX (rpl_mod->list_entry_l0[i], (NumPocTotalCurr - 1));
     }
@@ -2801,7 +2802,7 @@ gst_h265_parser_parse_slice_hdr (GstH265Parser * parser,
 
     if (pps->dependent_slice_segments_enabled_flag)
       READ_UINT8 (&nr, slice->dependent_slice_segment_flag, 1);
-    /* sice_segment_address parsing */
+    /* 7.4.7.1 slice_segment_address parsing */
     READ_UINT32 (&nr, slice->segment_address, n);
   }
 
@@ -2835,6 +2836,7 @@ gst_h265_parser_parse_slice_hdr (GstH265Parser * parser,
             (nal_reader_get_pos (&nr) - pos) -
             (8 * (nal_reader_get_epb_count (&nr) - epb_pos));
       } else if (sps->num_short_term_ref_pic_sets > 1) {
+        /*  7.4.7.1 short_term_ref_pic_set_idx */
         const guint n = gst_util_ceil_log2 (sps->num_short_term_ref_pic_sets);
         READ_UINT8 (&nr, slice->short_term_ref_pic_set_idx, n);
         CHECK_ALLOWED_MAX (slice->short_term_ref_pic_set_idx,
@@ -2855,6 +2857,7 @@ gst_h265_parser_parse_slice_hdr (GstH265Parser * parser,
         for (i = 0; i < limit; i++) {
           if (i < slice->num_long_term_sps) {
             if (sps->num_long_term_ref_pics_sps > 1) {
+              /* 7.4.7.1 lt_idx_sps */
               const guint n =
                   gst_util_ceil_log2 (sps->num_long_term_ref_pics_sps);
               READ_UINT8 (&nr, slice->lt_idx_sps[i], n);