diff --git a/media/parsers/h265_parser.cc b/media/parsers/h265_parser.cc
index 2b41700f0f51e..60674efb838ae 100644
--- a/media/parsers/h265_parser.cc
+++ b/media/parsers/h265_parser.cc
@@ -883,6 +883,28 @@ H265Parser::Result H265Parser::ParseSPS(int* sps_id) {
 
   // If an SPS with the same id already exists, replace it.
   *sps_id = sps->sps_seq_parameter_set_id;
+  // ParsePPS() validates several PPS fields (num_tile_columns_minus1,
+  // num_tile_rows_minus1, diff_cu_qp_delta_depth, diff_cu_chroma_qp_offset_depth,
+  // log2_parallel_merge_level_minus2, init_qp_minus26) against whichever SPS is
+  // present at PPS-parse time. If a new SPS with the same id changes any of the
+  // bounds those checks depend on, the previously-validated PPSes are no longer
+  // known-good and must not be shipped to the platform accelerator alongside the
+  // new SPS. Drop them so the stream is forced to re-send (and re-validate) a
+  // PPS. This mirrors FFmpeg's remove_sps() (libavcodec/hevc/ps.c).
+  auto old = active_sps_.find(*sps_id);
+  if (old != active_sps_.end()) {
+    const H265SPS& o = *old->second;
+    if (o.pic_width_in_ctbs_y != sps->pic_width_in_ctbs_y ||
+        o.pic_height_in_ctbs_y != sps->pic_height_in_ctbs_y ||
+        o.ctb_log2_size_y != sps->ctb_log2_size_y ||
+        o.log2_diff_max_min_luma_coding_block_size !=
+            sps->log2_diff_max_min_luma_coding_block_size ||
+        o.bit_depth_luma_minus8 != sps->bit_depth_luma_minus8) {
+      base::EraseIf(active_pps_, [&](const auto& kv) {
+        return kv.second->pps_seq_parameter_set_id == *sps_id;
+      });
+    }
+  }
   active_sps_[*sps_id] = std::move(sps);
 
   return res;