fix: MKV demuxer crash due to NULL file path

src/lib_ccx/ccx_demuxer.c

@@ -134,9 +134,13 @@ static int ccx_demuxer_open(struct ccx_demuxer *ctx, const char *file)
 			return -1;
 	}
 
+	struct lib_ccx_ctx *parent_ctx = (struct lib_ccx_ctx *)ctx->parent;
+	int saved_current_file = parent_ctx ? parent_ctx->current_file : -1;
 	if (ctx->auto_stream == CCX_SM_AUTODETECT)
 	{
 		detect_stream_type(ctx);
+		if (parent_ctx)
+			parent_ctx->current_file = saved_current_file;
 		switch (ctx->stream_mode)
 		{
 			case CCX_SM_ELEMENTARY_OR_NOT_FOUND:

src/lib_ccx/matroska.c

@@ -2005,6 +2005,7 @@ void matroska_parse(struct matroska_ctx *mkv_ctx)
 
 FILE *create_file(struct lib_ccx_ctx *ctx)
 {
+
 	char *filename = ctx->inputfile[ctx->current_file];
 	FILE *file = fopen(filename, "rb");
 	return file;

src/rust/src/demuxer/demux.rs

@@ -247,8 +247,12 @@ impl CcxDemuxer<'_> {
             }
         }
         // Stream mode detection
+        let saved_current_file = self.parent.as_ref().map(|p| p.current_file);
         if self.auto_stream == StreamMode::Autodetect {
             detect_stream_type(self, ccx_options);
+            if let (Some(parent), Some(saved)) = (self.parent.as_mut(), saved_current_file) {
+                parent.current_file = saved;
+            }
             match self.stream_mode {
                 StreamMode::ElementaryOrNotFound => {
                     info!("\rFile seems to be an elementary stream")