fix: use case-insensitive matching for seek parameter detection

The heuristic detection of playseek/tvdr parameters in query strings
used case-sensitive strstr(), causing parameters like "Playseek=" to
go unrecognized. This left the parameter in the upstream URL unprocessed
and prevented recent seek mode from triggering.

Switch to strcasestr() for detection, extraction, and removal of seek
parameters, preserving the original case when forwarding to upstream.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: stackia

e2e/test_rtsp_misc.py

@@ -447,7 +447,7 @@ def _build_seek_query(param_name: str, start_str: str, end_str: str) -> str:
             return "custom_seek=%s-%s&r2h-seek-name=custom_seek" % (start_str, end_str)
         return "%s=%s-%s" % (param_name, start_str, end_str)
 
-    @pytest.mark.parametrize("param_name", ["playseek", "tvdr", "custom_seek"])
+    @pytest.mark.parametrize("param_name", ["playseek", "Playseek", "tvdr", "custom_seek"])
     def test_recent_playseek_uses_clock_range(self, shared_r2h, param_name):
         rtsp = MockRTSPServer(num_packets=500)
         rtsp.start()
@@ -514,7 +514,7 @@ def test_recent_playseek_ignores_r2h_start(self, shared_r2h):
         finally:
             rtsp.stop()
 
-    @pytest.mark.parametrize("param_name", ["playseek", "tvdr", "custom_seek"])
+    @pytest.mark.parametrize("param_name", ["playseek", "Playseek", "tvdr", "custom_seek"])
     def test_boundary_playseek_is_forwarded(self, shared_r2h, param_name):
         rtsp = MockRTSPServer(num_packets=500)
         rtsp.start()

src/service.c

@@ -273,6 +273,7 @@ int service_extract_seek_params(char *query_start, char **out_seek_param_name,
   const char *seek_param_name = NULL;
   char *seek_param_value = NULL;
   int seek_offset_seconds = 0;
+  char heuristic_seek_name[16];
 
   if (!query_start || *query_start != '?' || !out_seek_param_name ||
       !out_seek_param_value || !out_seek_offset_seconds) {
@@ -354,18 +355,25 @@ int service_extract_seek_params(char *query_start, char **out_seek_param_name,
     logger(LOG_DEBUG, "Using explicitly specified seek parameter name: %s",
            seek_param_name);
   } else if (query_start) {
-    /* Heuristic detection with fixed priority: playseek > tvdr */
-    char *playseek_check = strstr(query_start, "playseek=");
+    /* Heuristic detection with fixed priority: playseek > tvdr
+     * Use case-insensitive matching and preserve original case */
+    char *playseek_check = strcasestr(query_start, "playseek=");
     if (playseek_check &&
         (playseek_check == query_start + 1 || *(playseek_check - 1) == '&')) {
-      seek_param_name = "playseek";
-      logger(LOG_DEBUG, "Heuristic: detected playseek parameter");
+      memcpy(heuristic_seek_name, playseek_check, 8);
+      heuristic_seek_name[8] = '\0';
+      seek_param_name = heuristic_seek_name;
+      logger(LOG_DEBUG, "Heuristic: detected playseek parameter (%s)",
+             seek_param_name);
     } else {
-      char *tvdr_check = strstr(query_start, "tvdr=");
+      char *tvdr_check = strcasestr(query_start, "tvdr=");
       if (tvdr_check &&
           (tvdr_check == query_start + 1 || *(tvdr_check - 1) == '&')) {
-        seek_param_name = "tvdr";
-        logger(LOG_DEBUG, "Heuristic: detected tvdr parameter");
+        memcpy(heuristic_seek_name, tvdr_check, 4);
+        heuristic_seek_name[4] = '\0';
+        seek_param_name = heuristic_seek_name;
+        logger(LOG_DEBUG, "Heuristic: detected tvdr parameter (%s)",
+               seek_param_name);
       }
     }
   }
@@ -380,8 +388,8 @@ int service_extract_seek_params(char *query_start, char **out_seek_param_name,
     char *search_pos = query_start;
     char *seek_start, *seek_end;
 
-    /* Iterate through all occurrences of the seek parameter */
-    while ((seek_start = strstr(search_pos, search_pattern)) != NULL) {
+    /* Iterate through all occurrences of the seek parameter (case-insensitive) */
+    while ((seek_start = strcasestr(search_pos, search_pattern)) != NULL) {
       if (seek_start > query_start && *(seek_start - 1) != '?' &&
           *(seek_start - 1) != '&') {
         search_pos = seek_start + strlen(search_pattern);
@@ -445,10 +453,10 @@ int service_extract_seek_params(char *query_start, char **out_seek_param_name,
              seek_param_name, seek_param_value);
     }
 
-    /* Remove all seek parameters from URL */
+    /* Remove all seek parameters from URL (case-insensitive) */
     if (seek_param_value) {
       char *remove_pos = query_start;
-      while ((seek_start = strstr(remove_pos, search_pattern)) != NULL) {
+      while ((seek_start = strcasestr(remove_pos, search_pattern)) != NULL) {
         if (seek_start > query_start && *(seek_start - 1) != '?' &&
             *(seek_start - 1) != '&') {
           remove_pos = seek_start + strlen(search_pattern);