DTS Audio?

Discussion in 'Apple TV and Home Theater' started by dpriest, Mar 11, 2015.

  1. dpriest macrumors member

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    Nov 18, 2014
    #1
    I have the ATV 3 and from what I have read, there is no current way to play MP4 movies with digital theater systems sound and it only supports Dolby Digital surround. Quite frankly, I find this very frustrating, because I have some content with high-quality DTS sound. Does anybody know of a way to do this or has anybody heard future Apple TVs supporting this?
     
  2. mic j macrumors 68030

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    Mar 15, 2012
    #2
    No way to play DTS. No indication it will be supported in the future as it (or at least was) an mp4 issue.

    Not sure what you mean by "digital theater systems". Dolby surround is a digital surround and the aTV supports that, just not DTS.
     
  3. cardsdoc macrumors 6502

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    #3
    DTS = Digital Theater Systems
     
  4. cyber16 macrumors 6502

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    Jan 12, 2013
    #4
    If I recall correctly the aiport express will pass the dts stream via the toslink.
    Do you have one to try? set the airport speakers on the apple tv to the express and see if that works.
    Problem may arise with lag out of sync with full bit rate dts streams

    If not, I have three or four of the older N models and could give it a test.
     
  5. mic j macrumors 68030

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    #5
    Duh!!! Been so long since I have run across the full name, it didn't even occur to me. :eek:
     
  6. eddyg macrumors 6502

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    #6
    MP4 certainly supports DTS:

    http://www.mp4ra.org/codecs.html

    Handbrake has been capable of muxing it into the MP4 container for a while now.

    Apple haven't enabled DTS pass-through though. Personally I've switched to Kodi/Xbmc now instead of the ATV for this and various other reasons.

    Cheers Ed.
     
  7. mic j macrumors 68030

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    Mar 15, 2012
    #7
    Thanks for that updated info. I was aware you could mux a DTS track into an mp4, have done it myself just for yuks, but was not aware that anything could actually play it.
     
  8. 2010mini macrumors 68040

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    Jun 19, 2013
    #8
    Doesn't the ATV have a audio pass through feature? I believe if you encode the MP4 with DTS on the secondary audio track. The ATV will pass through to your audio receiver.
     
  9. cardsdoc macrumors 6502

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    #9
    It will only pass through DD.
     
  10. 2010mini macrumors 68040

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    #10
    Bummer.
     
  11. Cave Man macrumors 604

    Cave Man

    #11
    Just to be clear, Dolby Surround is an analog matrix audio format (L, R, C, S), whereas Dolby Digital is digital, usually as 5.1.
     
  12. mic j macrumors 68030

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    #12
    Yes, sorry. I was not being very precise in that post.
     
  13. Cave Man macrumors 604

    Cave Man

    #13
    I knew you knew that, but in case someone else reads it and doesn't know, this should clear up them.
     
  14. GreatDrok macrumors 6502a

    GreatDrok

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    #14
    One option is to re-encode your DTS tracks into a high bit rate DD track. I've been re-encoding my BD rips from DTS to DD 640kbps for a while and they retain much of the grunt and surround activity that is typical of DTS and lacking in the lower bit rate DD tracks. Note that while HandBrake can decode DTS, there's little point ripping MKVs with the DTS-MA or TrueHD tracks because the Handbrake decoder will only handle the core formats to with DTS-MA it just gets the regular 1.4Mbps DTS core and for TrueHD it will likely already be a DD 640Kbps track so you just need to pass that through.
     
  15. dpriest thread starter macrumors member

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    Nov 18, 2014
    #15
    If I have an mkv with DTS I use vidcoder (Handbrake) to encode DD 5.1 at 640kbps to an mp4 and it sounds pretty good. Is that what you are recommending? If an mkv has DD already I just do ac3 passthru to make an mp4
     
  16. GreatDrok macrumors 6502a

    GreatDrok

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    #16
    Yeah, Handbrake. AC3 passthrough, or 640Kbps AC3 encode from DTS if there's no AC3.
     
  17. LV426 macrumors 6502a

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    Jan 22, 2013
    #17
    Muffled

    My AV receiver has various sound modes for different types of content. E.g. "Drama" or "SciFi". As well as a 5-channel stereo mode.

    Why does the centre (dialog) channel sound so poor in Drama or SciFi mode? All crispness is gone, and speech sounds muffled and harder to make out compared with the 5-channel stereo mode. Is that a limitation of the Apple TV Dolby digital signal, or something else?

    AV amp: Yamaha RX-S600
    Speakers: M&K
     
  18. GreatDrok macrumors 6502a

    GreatDrok

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    #18
    I have a similar Yamaha amp - it is most likely your centre speaker (either the quality or the settings on the amp for it.) I run everything flat and it sounds clear. The main thing I need to do is balance the audio levels for the various speakers because of differences in efficiency. You may need to dial the levels on the main pair back a bit to allow the centre channel to be more audible. Also, the rear channel shouldn't be obviously loud from your sitting position because you may end up with the surround channel drowning everything else out - ideally surround should be ambience rather than super obvious. With the old Dolby Surround, it was more about pulling the audio into the auditorium, but with 5.1 surround they were then able to steer the sound due to having stereo surrounds but the limited bit budget means that the surrounds aren't used all that much and most would go through the main three channels. DTS on the other hand has more bits to play with so you get more activity in the rear as well as it having more punch. If your sound system is set up well though, you should be able to get the most out of everything from mono through matrix surround (Dolby Surround) and discrete surround without having to fiddle with the settings each time you watch a film.

    Each of the DSP modes will tend to affect the sound quality so you may need to try various settings to find what suits. I tend to avoid the 'sport' or 'cathedral' settings as the former is too harsh and the latter heavy on the echoes.
     
  19. dpriest thread starter macrumors member

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    Nov 18, 2014
    #19
    I just addressed this issue 2 days ago. I have a Yamaha RX-V795A receiver that is over 15 years old and an NHT subwoofer. My wife would yell at me because I had the receiver turned up loud...it was hard to hear the voices of the center speaker, plus I love a true cinema experience. I moved into my house 3 years ago and couldn't find the remote to the receiver but after a Sat. night I went on a mission to find it and voila, I did. I used the remote to balance all 5 speakers, boosted the center and toned down the rears. That was it and problem solved. After all these years, I still don't understand all the dsp adjustments.
     
  20. LV426, Mar 17, 2015
    Last edited: Mar 17, 2015

    LV426 macrumors 6502a

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    Jan 22, 2013
    #20
    Thanks for the pointers. I have some investigation to do.

    You know something that would really help: an iTunes movie (running on Apple TV) that simply steps through all 6 speakers, with a mixture of dialogue and music samples. Any suggestions...

    I did download a THX tune-up app for the iPhone, but that doesn't seem to do 5.1 tests when using the Apple TV.
     
  21. mic j macrumors 68030

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    Mar 15, 2012
    #21
    My very old Sony AVR produces a test tone that rotates through the speakers so you can balance everything. Any chance yours does that?
     
  22. GreatDrok macrumors 6502a

    GreatDrok

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    #22
    Your amp should step through the channels with white noise to set the volume. Once you've done that, you will just need to find a DSP setting which suits your needs because there's no control over each individual channel's EQ other than saying the speakers are big or small, at least on my Yamaha anyway.

    If you really want to get things right, you might want to track down Video Essentials. I've used this since back in the day when I was on LaserDisc and my original DLP projection system. It works a treat for setting up your AV system. They have since done DVD and BD versions. Some DVDs or BDs even come with test cards and audio (Disney DVDs often have the THX tune up on them)

    A properly calibrated TV or projector, allied to a well balanced surround sound system is a joy to behold. I have a 100" DLP HD front projection system in my living room and rarely go to the cinema as a result.
     
  23. LV426 macrumors 6502a

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    Jan 22, 2013
    #23
    Yes, it does. In fact it also has a MIC so that it can auto balance speaker levels.

    However, that's not really what I need. I would like to be able to judge sound quality from each speaker, using the various DSP modes that are available and - rather importantly - sourced from the Apple TV, not directly from the amp's firmware. i can't judge the sound quality from a test tone or white noise.

    ----------

    My display (Pioneer Kuro) is well calibrated. You are right, it makes a big difference. I thought I was getting somewhere with the THX tune up, but it doesn't do a 5.1 test via Apple TV. Maybe some licensing matter, I don't know. It seems there's a stumbling block if you want to test sound quality from each speaker using Apple TV as the source. If Video Essentials is available on iTunes, that might be what I need.
     
  24. priitv8 macrumors 68020

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    #24
    With Final Cut Pro you could create one on your own.
     

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