Windows media player refuses to playback DTS audio

I have a .mp4 video file with DTS audio, and previously WMP was able to play it back just fine. After updating the CCCP codec pack however, WMP will only play the video but not the audio. The same video file works perfectly in other video players such as MPC.

I tried installing the k-lite mega codec pack (12.3.5) today, but it still would not play back audio. I tried the codec tweak tool and disabled stuff like media foundation and anything that might help with audio issues and mp4 files/dts audio, but it made no difference.

The one thing that worked was setting the codec tweak tool -> audio output -> audio bitstreaming to external device -> disabled. WMP will then play the audio back. If i have it set to enabled, it will not.

My setup is win 7 64 bit and i have a external DAC connected to the computer, and the computer is set to use SPDIF output. I am not sure if this means that the computer is using the onboard sound before playing it through the DAC somehow, or why WMP will not play the audio if "audio bitstreaming to external device" is enabled.

Can someone explain to me what is going on here? Why is only WMP having issues with mp4 files + DTS audio? I thought installing a codec pack would let WMP play the format with no issues? Why is it unable to do that?

The SPDIF output is failing. Do you actually have a receiver that is capable of decoding DTS? A DAC usually only functions as an external sound card. That doesn't count as an external device in the context of bitstreaming. Butstreaming means the audio is not decoded by the computer, but is send directly to another device for decoding.

If SPDIF does work in MPC, then the cause may be due to settings in WMP. Disable all the enhancements such as the equalizer.

Ah good point, it might not be capable of decoding DTS and MPC is automatically downmixing it.

I tried disabling everything in the enhancements part of WMP but it still wont play the audio. Which is weird because i used to play the same file in WMP before.

How do i get WMP to downmix it like MPC does?

The solution is simple: don't enable bitstreaming.