The reliable iPhone method
Large videos may fail when selected directly from Photo Library. Saving the original video to Files first gives Safari a normal file that it can hand to the converter.
- In Photos, open the video and tap Share.
- Choose Save to Files, then select On My iPhone or another local folder.
- Open VideoToMP3, choose the video from Files, and keep Safari in the foreground.
- When conversion finishes, tap Save MP3 and choose Save to Files in the Share sheet.
How to tell whether conversion started
“Preparing your video” means iPhone has not delivered the file yet, so conversion is not running. “Loading the converter” and “Converting to MP3” mean VideoToMP3 is actively working.
For long videos, keep the screen awake and avoid switching apps. iOS may pause or close heavy browser work when Safari is placed in the background.
If Photo Library stays stuck
Stop waiting after several minutes for a locally stored video. Save it to Files and select that copy instead. Also confirm the iPhone has enough free space for the source video, a temporary copy and the finished MP3.