diff --git a/whisper.sh b/whisper.sh
index 2b1d6d3..9aa6760 100755
--- a/whisper.sh
+++ b/whisper.sh
@@ -78,6 +78,15 @@ if [ -z "$FILE" ]; then
 	usage
 fi
 
+EXTENSION="${FILE##*.}"
+EXTENSION="${EXTENSION,,}"
+VALID_EXTENSIONS="mp3 wav aac ogg flac m4a wma opus aiff alac ape wv amr ac3 dts mka mp4 mkv mov avi webm m4v wmv flv mpg mpeg vob ts mts m2ts 3gp ogv"
+
+if [[ ! " $VALID_EXTENSIONS " =~ " $EXTENSION " ]]; then
+	echo "Error: formato no soportado (.${EXTENSION})"
+	exit 1
+fi
+
 # Verificar si whisper-cli está disponible
 if ! command -v "$WHISPER_CLI" &>/dev/null; then
 	echo "Error: whisper-cli no se encuentra en $WHISPER_CLI"