AC3-AAC-MP4.Ac3 seems to be the only one that plays true DTS 5.1

My media player only plays true 5.1 when audio is in AC3.I had to awhile back reformat my player because of bad firmware updates.So roled it back to 3.00.28 firmware.Should it play other audio formates in true DTS 5.1?.Thanks&hope some one can help.

Your subject is confusing. AC3 is not DTS, it is Dolby. AAC is not DTS, it is AAC. MP4 isn’t an audio format, it is a container.