SurroundByUs.com

what can i do to make it detect the DCADEC ?

By default the Dcadec (HD) decoder will be used. So you do not have to do anything special. I know that when you hit the DTS button in Application/Settings that it says that it will use the libav decoder, but that is a bug that got corrected in the next (upcoming) release.
When you convert a DTS (HD) stream you'll see which decoder is being used. So try it out and let me know should there still be a problem/question.

dts, dts hd and aac audio encoding is blank. i can't choose them to encode

Page 15 of the user guide.
For DTS/DTSWav you need to have the commercial Surcode DTS DVD or CD encoder installed or the free ffdcaenc (see link of my post of dec 26 2015 in this thread, p45. Hit the ffdcaenc button in Application/Settings (Audio Settings part) to set the path to the exe).
For DTSHD you need to have the commercial DTS-HD Master Audio Suite installed.
To see whether they are correctly installed go to Application/Settings (Audio Settings part) and hit the DTS Test button.
For Qaac you need to have qaac.exe installed (https://sites.google.com/site/qaacpage/). Hit the AAC/ALAC settings button in Application/Settings (Audio Settings part) to set the path to the exe file. In that section you can also set the path to the Nero AAC Decoder (ftp://ftp6.nero.com/tools/NeroAACCodec-1.5.1.zip).

i see
i thought that the dcadenc would be enough.
buyng master audio suite right now
by the way. this master suite is a very old program from 2010. i got a error message, but the encode was sucessfully. maybe it's because it works on 32 bits and it was made under windows xp. i have win 10. they need to update this >.<

Final Edit (hopefully):

I had a problem with dts files not being recognized by AudioMuxer.

By testing and testing I discovered that sometimes when trying to feed to Audiomuxer some dts files, mediainfo.exe crashed and locked the program. I went into the roaming data directory and discovered that the mediainfo version used is an old one. It's 0.7.61, dating back to October 22nd 2012. I downloaded the CLI version from here (https://mediaarea.net/download/binary/mediainfo/0.7.91/MediaInfo_CLI_0.7.91_Windows_i386.zip), which is just an exe file with no external DLL. I renamed the mediainfo.exe to a .bak version and copied the new version over in the C:\Users\gorman\AppData\Roaming\AudioMuxer\MediaInfo directory.

And all the files are working just fine. I advise to update the mediainfo version you use in the installer. Four years is a long time in this world.
Hope you'll find my journey useful. I spent long hours in solving this.

Thanks gorman for bringing this to my attention. Just for my collection of test files, would you be so kind to PM me a test DTS file that did not work.
Just for your info, if you replace the old exe/dll with the new MediaInfo exe, then some of the newer codecs (TrueHD+Atmos or DTS+DTS:X) will not be labeled correctly anymore. The older version will not have this problem.
In the next release of AudioMuxer I will upgrade some of the helper applications, including some of the mkv tools (since DTS:X does not play nice with the current outdated versions of these tools).
Thanks again....