[FIX] Resolve output artifact on Linux/WSL (line clearing)

Author: cfsmp3

docs/CHANGES.TXT

@@ -1,5 +1,6 @@
 0.96.6 (unreleased)
 -------------------
+- Fix: Clear status line output on Linux/WSL to prevent text artifacts (#2017)
 - Fix: Prevent infinite loop on truncated MKV files
 - Fix: Various memory safety and stability fixes in demuxers (MP4, PS, MKV, DVB)
 - Fix: Delete empty output files instead of leaving 0-byte files (#1282)

src/lib_ccx/utility.c

@@ -179,16 +179,21 @@ void mprint(const char *fmt, ...)
 	if (!ccx_options.messages_target)
 		return;
 	va_start(args, fmt);
-	if (ccx_options.messages_target == CCX_MESSAGES_STDOUT)
-	{
-		vfprintf(stdout, fmt, args);
-		fflush(stdout);
-	}
-	else
+
+	FILE *target = (ccx_options.messages_target == CCX_MESSAGES_STDOUT) ? stdout : stderr;
+
+	if (fmt[0] == '\r')
 	{
-		vfprintf(stderr, fmt, args);
-		fflush(stderr);
+#ifndef _WIN32
+		fprintf(target, "\r\033[K"); // Clear the line first
+		fmt++;			     // Skip the '\r' so only the clean text gets printed next
+#endif
 	}
+	// Windows (legacy console) does not support ANSI sequences; fallback to standard \r; and vfprintf below handles it the old-fashioned way.
+
+	vfprintf(target, fmt, args);
+	fflush(target);
+
 	va_end(args);
 }