Maximum number of audio files.

@Moeder
I'm sorry. It was running with different firmware.
I reconfirmed the operation.
It is operating normally.
The problem was clear.
I found that the sound becomes shorter when there are more files in the SD memory.

besides this small timing issue, does everything work for you?

If there are a large number of files in SD memory, there seems to be no problem except for trouble with audio playback.