DTS Passthrough help Apple TV 3

Discussion in 'Apple TV and Home Theater' started by Talae, Mar 10, 2013.

  1. macrumors newbie

    Mar 10, 2013
    Need some help here. I thought that using the optical output from the Apple TV into a reciever that can decode DTS would work.

    However none of my encodes work. I have a few that I set to AC3 and they work fine however any file that I am trying to stream from my PC will not work if it only has a DTS audio channel.

    Most of these were original mkv formats that I converted to mp4. Now that most of them are in mp4 format if i try to re-encode the file using Media Recode to get the audio into AC3, after conversion itunes will not add the file. No matter what i try iTunes will not add that file.

    Any suggestions or help?
  2. macrumors 68020

    Mar 15, 2012
    No support for dts in the mp4 format. You can include the track but nothing will play it, including the aTV. Not familiar with Media Recode, so I'm of no help there. I use Handbrake for all my mkv to mp4 transcodes.
  3. thread starter macrumors newbie

    Mar 10, 2013
    well screw me sideways........now i need to see if i can undelete all my mkv's...

    or do you know if handbrake will allow me to rencode it? Audio of the mp4's plays fine on my computer, so i assume handbrake can re-encode it?
  4. macrumors 68020

    Mar 15, 2012
    Let me make sure I understand what you have done. You have remuxed an mkv file to an mp4 keeping the DTS track in the file. That is, you have just changed containers (mkv to mp4) not transcoded the file from say, mpeg2 to mp4. Is that correct?
  5. thread starter macrumors newbie

    Mar 10, 2013
    Yes that would be correct.

    I have since tried just changing the DTS audio in the file to AC3, which works on my PC, however iTunes won't add it to the library.
  6. macrumors 68020

    Mar 15, 2012
    Well, unfortunately, you have hit a dead end with me on DTS conversion to AC3 on a PC. I know how to accomplish it on the Mac side, but that's of no help to you. I am pretty sure Handbrake could be used with minimal video quality loss since you have not already compressed the file in you conversion from mkv to mp4 and it would also do the dts to AC3 conversion. But no way to do it using HB without compression, if that is your requirement.

    Hopefully, other can help.
  7. thread starter macrumors newbie

    Mar 10, 2013
    I am going to try to repackage them back to MKV (if that's possible) then encode them with AC3. Not sure if it will work.

    I looked at handbrake and handbrake is telling me that it can't even detect the audio file.

    Do you have the steps for doing it on a MAC? I was actually thinking of buying one for better intergration with iTunes/appletv.
  8. macrumors 68020

    Mar 15, 2012
    You would convert the DTS track to AC3 using an app called mp4tools. Not sure I would drop a grand+ on a mac just to do it though. There has to be a way on the PC dark side.
  9. macrumors regular

    Aug 2, 2012
    Just encode the DTS track in the file. Just because the AppleTV does not allow you to use it does not mean some day there will be a device or software that will allow to you use the DTS. DVD movies are not that good of sound quality anyhow. Some are good while some are not so good. Especially the older movies. I find using the AppleTV3 preset in handbrake works just fine for standard DVD rips. You still get the 5.1 bitstream surround and all that stuff.
  10. thread starter macrumors newbie

    Mar 10, 2013
    I wish it was that easy (if i had the original mkv file, it would be). Handbrake won't even recognize the audio from the mp4's I created.

    I successfully converted a few of the files back to mkv's and then used handbrake to encode them to the appletv preset...what a pain...whole process took 1 1/2 hours per file...
  11. macrumors 65816


    Jul 23, 2008
    Here is another option, stop all this transcoding nonsense and get a WD Live type device.

    I own and love the Apple TV but I don't let it near my "mkv" movies.
    I want to see them as close to BR quality as I can.
    You drop the raw file on a USB device or stream it and you have 720/1080p, DTS or DD, and subtitles with no syncing or transcoding.
    I have both device sitting next to each other and switch the HDMI when I need to.
    The AppleTV is great for Apple content but unless you want to jailbreak it, get a $60 - $100 WD Live type device and save yourself the headache.
  12. macrumors 603

    Feb 4, 2008
    This, Apple TV fourth generation! I don't know if hardware limits the sound output or it's just the OS, BUT DO THIS. My neighbors are able to sleep too well at night, and I want them to think a T-Rex is about to escape from its pen.
  13. macrumors regular

    Aug 2, 2012

    If you look at the AC3 with AC3 passthrough in Handbrake, it shows the 448kbit's as the default. This is the maximum bit rate for AC3 anyways, so by using passthrough, you are getting max bitsteam of 448kbit's just like the disk. There is no loss of audio. That is if you are using a standard receiver with DD/DTS decoders built-in. The AppleTV does not even touch the audio bitstream, it passes it through to your receiver. That is why it is called passthrough.
  14. macrumors 603


    Feb 15, 2009
    Toronto, Canada
    Actually it's 640kbit's and the ATV2/3 supports it.
  15. dynaflash, Mar 14, 2013
    Last edited: Mar 14, 2013

    macrumors 68020

    Mar 27, 2003

    Edit: 640 is the max for ac3, that does not however mean all ac3 sources are 640. what you are seeing is a source with a 448 bitrate track. since it is ac3 passthru that is why you are seeing 448.
  16. macrumors 603


    Feb 15, 2009
    Toronto, Canada
    Handy for downmixing DTS or Blu Ray TrueHD audio.
  17. InfinityLore, Apr 16, 2013
    Last edited: Apr 16, 2013

    macrumors newbie

    Apr 16, 2013
    Apple may in future provide support for passthrough of a DTS (dts Digital) stream. However at present only DD (Dolby Digital) and AAC streams are supported in iTunes (ATV, iOS, etc) in an mp4 or m4v container. These containers can only store two audio streams plus (x264 codec) video. The m4v container specifically can only store a DD and/or AAC stream plus video. It is important to note the mp4 on the other hand can store a DTS stream but this won't be recognised by iTunes or other Apple products. Additionally to be fully compatible with iOS (iPhone/iPad which doesn't support DD) an AAC stream should always be included as track 1 in an mp4 or m4v. If only a DD stream or (in the case of mp4) a DTS stream is included the video will not play in iTunes at all or will but with no audio present.

    So this is my suggestion for anyone looking to preserve the DTS (1556 kbps) lossless track, to patiently await the day a tweak is made by Apple to just pass the signal through. Heck even if they don't you can keep the original audio and quality without conversion to DD (640 kbps). If you are on OSX there is a program in the Mac App store called MKV2M4V which will demux/remux mkv files to m4v/mp4. During the process the audio options presented will allow you to retain the DTS stream as audio track 2 (select AC3 passthrough), while creating a (320 kbps) AAC stream as track 1. This can only be done if the output file type is selected to be mp4. To include subtitles place an (identically named) srt file in the same location as the video file it is for (select and drag both files onto MKV2M4V app), and check the subtitles checkbox in the application. Also check the 'set tracks and chapters' option. Be aware this application does not transcode the video stream it just plucks (demuxes) it from the mkv container as is, which means no loss of quality from the source.

    The result is an mp4 file with 1 video stream and 2 audio streams (track 1 AAC, track 2 DTS). It can be dropped onto iTunes but when played only the AAC will be visible. To play the DTS audio use VLC Media Player and select audio track 2. If VLC is configured properly and your system supports AC3 passthrough (even OSX) you will get the DTS audio stream. A helpful tip is that if you notice the DTS audio is out of sync upon skipping through the video, simply select audio track 1, then select audio track 2 again a few seconds later while the video is playing. I would warn you though the GUI is not great in the application, however it does get the job done.

    If your source mkv has a DD audio stream then you can use an m4v container for output. This is an easy way to tell which files you have will have a DTS (mp4) or DD (m4v) audio stream.

    The trade off for using this method is the inability to get digital passthrough when using mp4, DTS and iTunes since only the AAC is available. However the upside is preservation of the original DTS audio stream. The alternative is to use some program to convert the DTS stream to a DD stream. In this scenario you would use an m4v container with AAC (320 kbps) for track 1 and DD (640 kbps) for track 2. When added to iTunes both tracks will be available, on iOS only the AAC stream will be available (this is why it's important to include it).

    Personally I chose to use mp4 to store DTS, then use VLC/Desktop/Laptop/TV for playback or suffer the 320 kbps AAC. Eventually Apple will undoubtedly elect to support DTS passthrough. With mp4 and m4v interchangeable (i.e. simply rename the file extension to change file type) when DTS support does come hopefully it is implied m4v will get support for it too.
  18. bucksaddle, Apr 17, 2013
    Last edited: Apr 17, 2013

    macrumors regular

    Dec 4, 2008
    They can store more than 2 audio streams (my Matrix m4v has 6 audio streams - 1 AAC, 1 AC3 plus the 4 commentaries and I can select any of them to play on the ATV) but the original point still stands, no DTS on the ATV as of yet.

    To get maximum benefit now and future proofing you could have 3 audio streams - 1 AAC, 1 AC3 converted from the DTS track and 1 with DTS passthru. You can do all of this in HandBrake now

    If you have an AC3 track and are playing the movie back on an iPhone / iPad to a compatible receiver (either via AirPlay or via HDMI) then the AC3 track will be used, so iOS does allow use of AC3. If you are playing back directly on the device without connection to an appropriate receiver then it will fall back to the AAC track - that's why it's important to include it
  19. macrumors regular

    Jun 5, 2012
    I am using iFlicks to transcode all my MKVs. It will create an AC3 track and an additional stereo track. Plus, and that is kind of cool, it will fill all the meta data automatically.
  20. macrumors 6502

    Oct 4, 2008
    A lot of the posters here are wrong - Apple devices do not choke with m4v files containing DTS tracks. iTunes will happily import, play and sync these files but you cannot select or play the DTS track. As has been suggested the most future-proof way to arrange m4v files is to have track 1 - AAC, track 2 - AC3, track 4 - DTS, track 5 (commentaries etc) - AAC etc

    Players like VLC and the recent XMBC builds can play back these DTS tracks - thus if you can get XBMC onto the ATV you may still be able to get to the DTS track (no jailbreak for ATV3 yet though).
  21. macrumors 68020

    Mar 27, 2003
    This is completely correct. The DTS track being present does not affect the ability to playback the file. As noted above you just cannot hear that track on an apple device. Yes, my hacked atv 1 running xbmc linux *can* playback a dts track in an mp4 (thanks davilla).
  22. macrumors 6502a

    Feb 27, 2010
    This^^^. I've been converting to M4V with 3 audio tracks (2ch, DD5.1, DTS). VLC now supports playing M4V with DTS audio, so I have a good quality file with an uncompressed audio for when ATV supports DTS or if I want to reconvert the file. Hoping this gives me a leg up in the future, but never know what will happen next.
  23. macrumors newbie

    Jun 17, 2013
    What process are you using to do this? I created an m4v with an AAC and AC3 and DTS track just as you said but it won't add to itunes. It works if I have AAC and AC3, but if I add the DTS track it won't work.
  24. macrumors 6502a

    Feb 27, 2010
    I'm mostly selecting the High Profile preset, and then adding in the extra sound tracks, but if you select the ATV3 preset and add in the DTS as the last audio track that should be fine as well. The order for the audio must be: 1st = 2ch, 2nd = 5.1 Dolby, and the last must be DTS.

    The one thing I didn't mention that might be your issue is that I have only been able to do this with basic 5.1 DTS tracks and not any of the HD, MA or 6.1 tracks. I'm not sure if I ever had issues importing them (I'd usually just have an issue with playback in VLC where no audio would play regardless of the track selected).

    And when you say you can't import are you getting an error, or is it just refusing to let you drag and drop (or select the video from the Import window)?
  25. macrumors newbie

    Jun 17, 2013
    What software are you using?

    I don't get an error, when I drag and drop it just doesn't show up.

    And yes, I'm trying to include DTS-MA track, if it wasn't there would be no point in including the DTS track.

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