# Question about REMUXing .mkv files



## jonathan1107 (Mar 19, 2015)

Hi I've recently come across a small problem. I have some movie files that I've tried to play on my HDTV and I get the "audio format not supported" error message when I try to play them, but the video image plays perfectly after that though... so it's only the audio aspect that is a problem...

So I did some research on google and used MEDIAINFO to find out what formats I have. My audio formats for the files that seem to work ok (no audio error message) use DTS and the like (format)

whereas the files I have problems with use "True HD" audio formats ... So I read on the web that I can use avidemux (Software) to remux only the audio aspect of the file into something like ac3 lav format...

That seems like a good idea but I was wondering if that's going to compress the audio even further and kill the quality of the audio stream or no? and If I do this there are some bitrate settings I can choose for remuxing (all the way up to 448) is there a better choice?

I tried 448 earlier and my PC apparantly couldn't handle it because the software crashed. 

any tips and suggestions?


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## Uplink10 (Mar 19, 2015)

Is the audio that won`t play Dolby Atmos (http://en.wikipedia.org/wiki/Dolby_Atmos)?
I had a few problems last year when I tried playing Dolby Atmos on PC with MPC-HC because LAV Filters and ffdshow did not support it yet.
If your HDTV does not support Dolby Atmos you will have to extract TrueHD from Dolby Atmos audio stream because the Dolby Atmos substream is added to TrueHD stream (Dolby Atmos is embedded in True HD). Then you can also convert TrueHD to DTS-HD. Converting your audio to DTS-HD from TrueHD will lose some quality but it will probably not be noticeable(the original quality/structure will not be preserved). If you convert HD audio stream (DTS-HD, TrueHD) to AC-3 you will lose a lot of quality because AC-3 has lower maximum bitrate.

Edit:
There is also another reason why your TrueHD stream will not play on HDTV, "DTS-HD MA" and "DTS-HD Hi Res" uses scalable structure which means you have a core audio (usually  1500 Kbps) which you can extend with extension (MA, Hi Res) to higher bitrates so it is possible your HDTV only plays (supports) core audio track, but you can`t do that with TrueHD because TrueHD does not support core audio + extension.

For example if you have "DTS-HD MA" (usually around 5000 Kbps) and your HDTV does not support the extension it it will only play the DTS "core" audio track which has bitrate usually 1500 Kbps. This happens with both DTS-HD *Master Audio (MA)* and DTS-HD * High Resolution Audio (Hi Res). *
For example if you have TrueHD and your HDTV does not support it you can`t revert to "core" audio stream.

Short comparison:

-DTS-HD MA is lossless, scalable (core + extension)
-DTS-HD Hi Res is lossy, scalable (core + extension)

-Dolby Digital (also AC-3) is super lossy
^^^^^usually this track is included with Bluray movies alongside lossless audio stream

-Dolby TrueHD is lossless, not scalable
-Dolby Atmos is embedded in Dolby TrueHD stream
-Dolby Digital Plus (*DD+*) is lossy, not scalable


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## newtekie1 (Mar 19, 2015)

I personally use xmedia recode. I just tell it to copy the video and then re-encode the audio in a format that is compatible.  In my case I also have it change the file container from MKV to MP4 because I have some media devices that don't play MKV files.


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