Fix a uint32 truncation in gsth264parser

docker/build-gstreamer/compile

@@ -33,6 +33,7 @@ git apply /compile-patch/0001-pad-Check-data-NULL-ness-when-probes-are-stopped-f
 git apply /compile-patch/0001-Reduce-logs-verbosity-in-webrtcbin-when-a-FEC-decode.patch
 git apply /compile-patch/0001-glvideomixer-update-API-to-be-compatible-with-versio.patch
 git apply /compile-patch/0001-GstAudioAggregator-fix-structure-unref.patch
+git apply /compile-patch/0001-gsth264parser-fix-uint32-to-int32-truncation.patch
 
 # This is needed for other plugins to be built properly
 ninja -C build install

docker/build-gstreamer/patch/0001-gsth264parser-fix-uint32-to-int32-truncation.patch

@@ -0,0 +1,115 @@
+From 282a528c7234d1cb89422db0fcce56385b0507b5 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Lo=C3=AFc=20Le=20Page?= <llepage@igalia.com>
+Date: Fri, 31 Oct 2025 13:27:47 +0100
+Subject: [PATCH] gsth264parser: fix uint32 to int32 truncation
+
+The H264 parser is using int32 to compute the framerate numerator and
+denominator while the SPS block holding the original values used for
+this computation are stored on uint32. On corner cases it may lead to a
+truncation of the final values leading to an invalid framerate.
+
+This patch is shifting right the numerator and denominator until both
+values may be stored on int32. It may introduce a small computation
+error with odd values but negligeable taking into account the huge
+initial values > max_int32.
+---
+ .../gst-libs/gst/codecparsers/gsth264parser.c |  9 +++-
+ .../tests/check/libs/h264parser.c             | 48 +++++++++++++++++++
+ 2 files changed, 55 insertions(+), 2 deletions(-)
+
+diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth264parser.c b/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth264parser.c
+index ea3c6fb995..5095bcea73 100644
+--- a/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth264parser.c
++++ b/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers/gsth264parser.c
+@@ -2946,8 +2946,8 @@ void
+ gst_h264_video_calculate_framerate (const GstH264SPS * sps,
+     guint field_pic_flag, guint pic_struct, gint * fps_num, gint * fps_den)
+ {
+-  gint num = 0;
+-  gint den = 1;
++  gint64 num = 0;
++  gint64 den = 1;
+
+   /* To calculate framerate, we use this formula:
+    *          time_scale                1                         1
+@@ -2998,6 +2998,11 @@ gst_h264_video_calculate_framerate (const GstH264SPS * sps,
+     }
+   }
+
++  while (num > G_MAXINT32 || den > G_MAXINT32) {
++    num >>= 1;
++    den >>= 1;
++  }
++
+   *fps_num = num;
+   *fps_den = den;
+ }
+diff --git a/subprojects/gst-plugins-bad/tests/check/libs/h264parser.c b/subprojects/gst-plugins-bad/tests/check/libs/h264parser.c
+index ddf4fe50d4..1ddab3bea7 100644
+--- a/subprojects/gst-plugins-bad/tests/check/libs/h264parser.c
++++ b/subprojects/gst-plugins-bad/tests/check/libs/h264parser.c
+@@ -1023,6 +1023,53 @@ GST_START_TEST (test_h264_split_avc)
+
+ GST_END_TEST;
+
++// This SPS block with vui parameters defines:
++// - frame_mbs_only_flag: 1 (progressive)
++// - time_scale: 4294967294 (overflows int32 capacity)
++// - num_units_in_tick: 71834980
++// The expected framerate is 29,894678707 fps.
++static const guint8 nalu_sps_with_overflow_framerate[] = {
++  0x00, 0x00, 0x00, 0x01, 0x27, 0x64, 0x00, 0x1f,
++  0xac, 0x72, 0x14, 0x05, 0x00, 0x5b, 0xb0, 0x11,
++  0x04, 0x48, 0x1d, 0x64, 0xff, 0xff, 0xff, 0xfe,
++  0xe2, 0x20, 0x00, 0x74, 0xc1, 0x00, 0x00, 0x74,
++  0xc1, 0x3b, 0xde, 0xe0, 0x3e, 0x10, 0x08, 0x32,
++  0xc0
++};
++
++GST_START_TEST (test_h264_parse_overflow_framerate)
++{
++  GstH264ParserResult res;
++  GstH264NalUnit nalu;
++  GstH264SPS sps;
++  gint fps_num, fps_den;
++  GstH264NalParser *const parser = gst_h264_nal_parser_new ();
++
++  res = gst_h264_parser_identify_nalu (parser, nalu_sps_with_overflow_framerate,
++      0, sizeof (nalu_sps_with_overflow_framerate), &nalu);
++  assert_equals_int (res, GST_H264_PARSER_NO_NAL_END);
++  assert_equals_int (nalu.type, GST_H264_NAL_SPS);
++  assert_equals_int (nalu.size, 37);
++
++  res = gst_h264_parser_parse_sps (parser, &nalu, &sps);
++  assert_equals_int (res, GST_H264_PARSER_OK);
++  fail_unless (sps.valid);
++  fail_unless (sps.frame_mbs_only_flag);
++  fail_unless (sps.vui_parameters_present_flag);
++  fail_unless (sps.vui_parameters.timing_info_present_flag);
++  assert_equals_uint64 (sps.vui_parameters.time_scale, 4294967294);
++  assert_equals_uint64 (sps.vui_parameters.num_units_in_tick, 71834980);
++
++  gst_h264_video_calculate_framerate (&sps, 0, 0, &fps_num, &fps_den);
++  assert_equals_int (fps_num, 2147483647);
++  assert_equals_int (fps_den, 71834980);
++
++  gst_h264_sps_clear (&sps);
++  gst_h264_nal_parser_free (parser);
++}
++
++GST_END_TEST;
++
+ static Suite *
+ h264parser_suite (void)
+ {
+@@ -1039,6 +1086,7 @@ h264parser_suite (void)
+   tcase_add_test (tc_chain, test_h264_create_sei);
+   tcase_add_test (tc_chain, test_h264_decoder_config_record);
+   tcase_add_test (tc_chain, test_h264_split_avc);
++  tcase_add_test (tc_chain, test_h264_parse_overflow_framerate);
+
+   return s;
+ }
+-- 
+2.43.0
+