update ffmpeg output return to resolve error

thu.sh

@@ -627,6 +627,14 @@ img_wh_get () {
     fi
 }
 
+video_info_ffmpeg () {
+    if [[ -z "$is_cmd_ffmpeg" ]]; then
+        fail "$msg_cmd_not_found_ffmpeg"
+    fi
+
+    ffmpeg -i "$1" 2>&1
+}
+
 video_duration_ffmpeg_parse_ss () {
     duration_match=""
 
@@ -637,17 +645,13 @@ video_duration_ffmpeg_parse_ss () {
         fi
     done < <(printf '%s\n' "$1")
 
-    if [[ -z "$duration_match" ]]; then
-        fail "video duration could not detected"
-    fi
-
     IFS=" " read -r HOURS MINUTES SECONDS <<< "${duration_match//:/ }"
 
     duration_ss=$((10#$HOURS * 3600 + 10#$MINUTES * 60 + 10#$SECONDS))
     if [[ "$duration_ss" =~ $numint_re ]]; then
         printf '%s\n' "$duration_ss"
     else
-        fail "video duration could not detected: $1" 
+        fail "video duration could not be detected: $1" 
     fi
 }
 
@@ -758,18 +762,14 @@ thumb_create_from_epub () {
 thumb_create_from_video () {
     vid_path=$1
     vid_wh_max=$2
-    vid_ffmpeg_output=$(ffmpeg -i "$1" 2>&1)
+    vid_ffmpeg_output=$(video_info_ffmpeg "$1")
     vid_duration_ss=$(video_duration_ffmpeg_parse_ss "$vid_ffmpeg_output")
     vid_wh_native=$(video_resolution_ffmpeg_parse "$vid_ffmpeg_output")
     vid_wh_scaled=$(wh_scaled_get "$vid_wh_native" "$vid_wh_max")
     vid_frame_ss=$(($vid_duration_ss / 5))
     vid_thumb_path=$(
         cachedir_path_get "$cachedir" "video" "$vid_wh_scaled" ".png")
 
-    if [[ -z "$is_cmd_ffmpeg" ]]; then
-        fail "$msg_cmd_not_found_ffmpeg";
-    fi
-
     ffmpeg \
         -ss "$vid_frame_ss" \
         -i "$vid_path" \