diff --git a/src/main/ffmpeg.ts b/src/main/ffmpeg.ts
index 1dcc2cc5..8713b9ce 100644
--- a/src/main/ffmpeg.ts
+++ b/src/main/ffmpeg.ts
@@ -25,11 +25,12 @@ export function setCustomFfPath(path: string | undefined) {
 }
 
 function escapeCliArg(arg: string) {
+  // todo change String(arg) => arg when ts no-implicit-any is turned on
   if (isWindows) {
     // https://github.com/mifi/lossless-cut/issues/2151
-    return /[\s"&<>^|]/.test(arg) ? `"${arg.replaceAll('"', '""')}"` : arg;
+    return /[\s"&<>^|]/.test(arg) ? `"${String(arg).replaceAll('"', '""')}"` : arg;
   }
-  return /[^\w-]/.test(arg) ? `'${arg.replaceAll("'", '\'"\'"\'')}'` : arg;
+  return /[^\w-]/.test(arg) ? `'${String(arg).replaceAll("'", '\'"\'"\'')}'` : arg;
 }
 
 export function getFfCommandLine(cmd: string, args: readonly string[]) {
diff --git a/src/renderer/src/hooks/useFfmpegOperations.ts b/src/renderer/src/hooks/useFfmpegOperations.ts
index 238669f7..7322cb7f 100644
--- a/src/renderer/src/hooks/useFfmpegOperations.ts
+++ b/src/renderer/src/hooks/useFfmpegOperations.ts
@@ -615,7 +615,11 @@ function useFfmpegOperations({ filePath, treatInputFileModifiedTimeAsStart, trea
 
   // This is just used to load something into the player with correct duration,
   // so that the user can seek and then we render frames using ffmpeg & MediaSource
-  const html5ifyDummy = useCallback(async ({ filePath: filePathArg, outPath, onProgress }) => {
+  const html5ifyDummy = useCallback(async ({ filePath: filePathArg, outPath, onProgress }: {
+    filePath: string,
+    outPath: string,
+    onProgress: (p: number) => void,
+  }) => {
     console.log('Making ffmpeg-assisted dummy file', { filePathArg, outPath });
 
     const duration = await getDuration(filePathArg);
@@ -625,7 +629,7 @@ function useFfmpegOperations({ filePath, treatInputFileModifiedTimeAsStart, trea
 
       // This is just a fast way of generating an empty dummy file
       '-f', 'lavfi', '-i', 'anullsrc=channel_layout=stereo:sample_rate=44100',
-      '-t', duration,
+      '-t', String(duration),
       '-acodec', 'flac',
       '-y', outPath,
     ];