[How to convert] DTS to AC3 [in Mkv container]

Discussion in 'Apple TV and Home Theater' started by GA84, Feb 28, 2009.

  1. GA84 Guest

    Oct 16, 2008
    I'm a complete noob when it comes to converting video/audio on a Mac and I was hoping someone could tell me the easiest way to do the following conversion in Mac OS X;

    Mkv container containing
    - "H.264" HD video stream
    - "DTS Coherent Acoustics" audio stream

    Mkv container containing
    - "H.264" HD video stream (passed through and untouched)
    - "AC3" audio stream (converted "DTS Coherent Acoustics" audio stream)

    In Windows one could to this quite easily by using PopCorn MKV AudioConverter. The video stream in the Mkv container and the Mkv container itself would be left untouched and the DTS track would be converted into a AC3 track. And because the video track would be left untouched, converting an entire HD movie would be done in less than 10 minutes (depending on your processor, of course).

    Is there a similar app for Mac OS X? And if not, what would be the easiest way to do the conversion in Mac OS X?

    Any help would be greatly appreciated.
  2. tofagerl macrumors 6502a


    May 16, 2006
    I'm after the same thing. I had a nice script called mkvdts2ac3 from the NetworkMediaTank forums that with some adaptation served me well, but I switched to FreeNAS on my fileserver, so now I need a mac solution.
  3. johnnj macrumors 6502a

    Dec 11, 2008
    Not here
    I use the same NMT script myself, but I keep all my transcoding/ripping related shenanigans to my Windows boxes. How about if you run it under VMware? I'm sure there'll be a non-trivial performance hit, but it's better than nothing, right?

  4. phrehdd macrumors 68040


    Oct 25, 2008
    I do my "changes" in Fusion running XP. I do use a different set of tools but it works fairly fast and works admirably. I guess it would also depend on the system you have and how you set it up. Parallels can do it as well.

    I opt for Fusion as it can also see my Blu Ray burner that I have mounted internally in my Mac Pro 2.66 (connected via SATA cable to the mobo). A decent external blu ray player via firewire/usb should work well too. My apps used regularly are AnyDVDHD and TSMuxer. For some down conversions of audio I use primarily Eacto3. If audio is challenged then I run it thru "Delaycut" with default settings. Only app that you pay for is AnyDVDHD.

    If you already have files, then TSMuxer, EACto3, and on the Mac side - Handbrake (if you need to go with other types of formats).

    In short, Yes virtual Windows does work and speed is dependent on your set up.

    - Phrehdd
  5. Sedulous macrumors 68020


    Dec 10, 2002
    Unless you are tied to .mkv for some reason, why not use MKVTools? Choose to convert to .mp4, set video to passthrough (i.e. no re-encoding), and then choose the audio format of your choice AC3, AAC 5.1/2.0, etc. AppleTV will be more happy with mp4 anyways.
  6. andre.abreu, Jan 11, 2011
    Last edited: Jan 11, 2011

    andre.abreu macrumors newbie


    Jan 11, 2011
    Brasil, Rio de Janeiro
    I prefer do it in steps ...

    To converto only audio track!

    mkvinfo video.mkv #to identify audio track (i.e. 2)

    mkvextract tracks video.mkv 2: path/audio_track.DTS #to extract

    after I use ffmpeg to convert!

    ffmpeg -i path/audio_track.DTS -acodec ac3 -ac 6 -ar 48000 -ab 640k path/audio_track.AC3

    and merge on mp4/m4v using subler or moatroska file using mkvmerge.

    This method is very secure to obtain better quality in Dolby Digital file!

    to converto all video tracks to a MP4 file .. is simple with ffmpeg (or handbrake)

    ffmpeg -i movie.mkv -vcodec copy -acodec ac3 -ac 6 -ar 48000 -ab 640k -f mp4 movie.mp4

    for more ffmpeg option go to http://www.ffmpeg.org/ffmpeg-doc.html

    Remember to watch the video on the new apple tv it should be Main@3.1 or higher!

    I hope help! and sorry my english!
  7. Firewolve macrumors member

    Jul 21, 2009
    Thanks Andre, that really helped me a lot!

    My routine to convert mkvs to m4vs (under windows - as my server isn't running OS X) is now:

    1) extract video and audio tracks from mkv (mkvextract)
    2) convert existing dts-tracks to ac3 5.1 and aac 2.0 and existing ac3 5.1 tracks to aac 2.0 (ffmpeg)
    3) mux h264-track + one ac3 and aac track per language into one m4v file (YAMB)

    I'm not too happy with YAMB which takes quite a long time to mux the files but at least it seems to work.
  8. andre.abreu macrumors newbie


    Jan 11, 2011
    Brasil, Rio de Janeiro
  9. Firewolve macrumors member

    Jul 21, 2009
    Unfortunately it doesn't run on Windows and I don't really want to use two computers for this job :)
    Have you had any success in using ffmpeg to mux the files?
  10. BlackMangoTree macrumors 6502a

    Sep 30, 2010
  11. Firewolve macrumors member

    Jul 21, 2009
    That's right but for the audio conversation ffmpeg works just fine :)
  12. Rizvi1 macrumors 6502a

    Mar 29, 2006
    Laurel, MD (Baltimore, MD / Washington, DC area)
    Thanks for the advice, that's what I just followed.

    I had finished downloading a 4.68 GB movie to my Mac Mini in .mkv format with dts 6ch which I wanted to watch on our family room TV.

    I think my Samsung LED TV (un46B7000) can handle the .mkv file on a usb. The problem is that it won't read the USB drive in its Mac OS Extended (Journaled) state. If I convert to MS-DOS (FAT) , I don't think I can fit over a 4gb file on it. I could fire up my parallels (only PC in the house) and convert the USB to whatever format windows uses and then try to get it on there from there but that seemed too hard.

    So, the only option left was to make it a .mp4 to watch on our TV. Did a video pass thru and AAC (5.1) (since the Pass Thru option for Audio is in red - not recommended - for MP4) and have the Device as PS3.The video extraction was fast but the audio conversion took around 16 or 17 minutes. Then MP4 Muxing another 6 or 7 minutes I think- I think the muxing was 3 steps total.

    Would you mind explaining your audio conversion step? I was confused by it - I just converted my DTS 6ch to aac 5.1
  13. mynane, Nov 24, 2011
    Last edited: Nov 24, 2011

    mynane macrumors newbie

    Nov 24, 2011
  14. HandySam macrumors member

    May 9, 2011
    You can use Xvid4PSP (Windows) I use this one because with certain movies when I extract the streams out of mkv and convert audio separately then you have a chance that when merged the audio will not be in sync with video.

    Xvid4PSP does all this in 1 step and it has a feature "smart sync" that made my problem disappear (audio sometimes not in sync with video (more to the end)).

    On Mac you could use Subler (with Perian, only to AAC), MP4tools or remux.

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