Transcoded AV1 video cannot be saved to Photos on iPhone

Using following command to transcode a HEVC video to AV1. The result can be played in File or nPlayer, but can't be saved to Photos.

The device is iPhone17pro, so there shouldn't be problems decoding the video.

ffmpeg -i IMG_1802.MOV -c:v libsvtav1 -preset 4 -crf 20  -c:a copy -map_metadata 0 -svtav1-params "tune=0:keyint=60:film-grain=10:film-grain-denoise=0:lookahead=120" output.mp4