IOS 18 below FFmpeg subtitle synthesis log [Parsed_subtitles_0 @ 0x301b37650] Using font provider fontconfig [Parsed_subtitles_0 @ 0x301b37650] fontselect: (PingFangSC-Semibold, 400, 0) -> /System/Library/Fonts/LanguageSupport/PingFang.ttc, 8, PingFangSC-Semibold IOS 18 FFmpeg subtitle synthesis log [Parsed_subtitles_0 @ 0x303e825d0] Using font provider fontconfig [Parsed_subtitles_0 @ 0x303e825d0] fontselect: (PingFangSC-Regular, 400, 0) -> /System/Library/Fonts/Core/HiraginoKakuGothic.ttc, 10, . HiraKakuInterface-W4 [Parsed_subtitles_0 @ 0x303e825d0] Glyph 0x8FD9 not found, selecting one more font for (PingFangSC-Regular, 400, 0) [Parsed_subtitles_0 @ 0x303e825d0] fontselect: (PingFangSC-Regular, 400, 0) -> /System/Library/Fonts/Core/LastResort.otf, 0, LastResort In normal characters, there may be some garbled characters, such as 0x8FD9 mentioned in the log, corresponding to "这" Traditional Chinese and Simplified Chinese Normal font: Russian, Korean, Japanese, French, English, German IOS 18 below FFmpeg subtitle synthesis log fontselect: (PingFangSC-Semibold, 400, 0) -> /System/Library/Fonts/LanguageSupport/PingFang.ttc, 8, PingFangSC-Semibold IOS 18 FFmpeg subtitle synthesis log fontselect: (PingFangSC-Regular, 400, 0) -> /System/Library/Fonts/Core/HiraginoKakuGothic.ttc, 10, . HiraKakuInterface-W4 In iOS 18, the selected font has changed and instead of continuing to use PingFang.ttc, HiraginoKakuGothic. Has iOS changed the PingFang font directory, causing ffmpeg to be unable to use system fonts for subtitle synthesis