Frostylou - How are you connected and what settings are you using on the player? Also, what's the player model number?
If you are using HDMI, it is possible that the handshake tells the player that the TV lacks a DTS decoder and, as a result, the player then decodes and outputs multichannel PCM. If that is what's happening, you would be getting the DTS core, not the lossless dts-MA track. But, as previously noted, the core sounds great, often as good as lossless.
Does your soundbar/TV tell you the format of the audio it is receiving? Receivers do that. But, I don't know anything about your combo device.
btw, "transcoding" is not likely the proper term here. Transcoding means substituting one codec for another. If the player sends a Dolby track when playing a DTS track, that's transcoding (decodes and re-encodes to a new format). If it sends PCM, that's just decoding.