DTS-HD Master Audio (DTS-HD MA), and DTS-HD High Resolution are both various versions of DTS-HD. The Master Audio supports unlimited channels and word lengths of upto 24-bits and a sampling frequency of 192KHz. This is in multi channel. In two channel, Master Audio supports sound encoded at 24/96. The Master Audio can support data transfer at variable bit rate upto 24.5 Mbits/second.
Where disc size is an issue, DTS uses a slightly downgraded version of the same audio encoded at a maximum of 6 MBits/second. The sampling frequency is also stepped down to 96KHz.
The specifications of both Dolby TrueHD and DTS-HD are identical excepting for the transfer rates. DTS supports 24.5 MBits/Second while Dolby supports 18 Mbits/second. This could be the reason why you find DTS 'better' though supporters of Dolby will argue with you.
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