Apple TV 2 and DTS audio

Hi Brian,

I came across your post DTS-encoded music plays perfectly over Airtunes; not on Optical Digital Out And I'm posting here because the previously mentioned post has been archived & I couldn't find another way to get in touch! If anyone feels it's important enough to create a new thread then please by all means do so.

Anyway you mention:

Brian Williams2 wrote:

I quickly learned that I cannot rip those track into iTunes,

I want to do exactly the same as you and have almost got there but not quite. This is what I have been able to do so far.

This works for DTS & ac3

If you're familiar with the command line:

Download ffmpeg binary for OS X:

http://go.to/osxffmpegcompiling

navigate to the binary in terminal:

./ffmpeg -i input.VOB -vn -acodec copy output.m4a

or if you have the stream directly

./ffmpeg -i input.dts -vn -acodec copy output.m4a

This will encapsulate the DTS stream unchanged into .m4a container however it will not import into iTunes.

If this make no sense to you could use iffmpeg although it is shareware

http://www.macupdate.com/app/mac/35846/iffmpeg

Something interesting I noticed is that when converting a DTS wav (from your Swedish National Radio link) you can transcode it into apple lossless and it still plays as DTS! So there must be a way of encapsulating DTS in an m4a file as iTunes can do it. But I can't find a way with Mac OS to do it. Apparently with "AC3filter tools" it is possible in widows to encapsulate DTS into a wav file. So then one could import the wav to iTunes. But it would be nice to have an all mac solution.

I have tried with ffmpeg to encapulate vob/dts to wav but unfortunately unsuccessfully.

This walkthrough isn't what we want as they transcode the audio rather that just re-encapsulate it. But it is still interesting: http://www.beatmixed.com/2008/03/05/extracting-dts-on-a-mac/

There may be a way of doing what we want with libDTS that is mentioned in the previous link.

Anyway I hope you either have a solution that you may share or that this may encourage you to find one! I only have a few DTS encoded audio DVDs and have reached the end of my patience as to finding a solution!

But I may again feel the need to listen to "The original Quadraphonic mix by Alan Parsons" of "the Dark Side of the moon" without the hassle of using a DVD player!

Have you had any new successes?

WIth my first generation AppleTV, I can have iTunes send audio DTS files (encoded in Apple Lossless) to the hard disk of the AppleTV and my home theater successfully plays the surround sound tracks.

Today I just tried it for the first time with my AppleTV 2 using the same file from iTunes but over the Computers menu since, of course, the AppleTV 2 does not have an internal hard drive. And I only get the typical audio white noise.

I would like to play my audio DTS library in this way through my AppleTV 2 on my home theater.

Something you may find interesting is that you can passthrough DTS & DTS HD with HandbrakeCLI. Of course it won't work with the apple TV but interesting if you want to preserve the audio of the original.

As to creating wav files with DTS passthrough. A couple of thing have come to my attention.

First of all libDTS in now called libdca (http://www.videolan.org/developers/libdca.html). You can install it with MacPorts (http://www.macports.org/ports.php?by=name&substr=libdca).

There is a GNOME app that allows DTS to wav conversion named SoundConverter (http://soundconverter.org/). I may try it out with a bootable linux usb key. Seeing how I would do this only very rarely I wouldn't mind booting into Linux to convert the rare files I have so that I could at last achieve DTS audio from an audio DVD in iTunes. As I previously mentioned I was able to convert a DTS wav file to a DTS apple lossless m4a file and achieve DTS passthrough with iTunes (directly connected to a DAC). So once succesful in converting the DTS file to a DTS wav file, it would be easy to convert it into an apple lossless m4a file so that it would take up less space and still achieve DTS passthrough with a exact copy of the audio from the DVD. If I get around to it I will report on how it goes.

Thanks for your reply and good luck with the quest for DTS!

As of HandBrake 0.9.6 you can achieve DTS & DTSHD passthru to an MP4 container.

Brian

I think the issue may well relate to AppleTV 2/3 tinkering with bitrates.

AppleTV1 always output audio files at CD quality, 16 bit//44.1 kHz, so an uncompressed source containing DTS would just pass through as linear PCM at that rate.

AppleTV2 and 3 however upsample all audio to 16 bit 48 kHz which would wreck the original data.

AC

Are you equalizing your music in iTunes? That could be the problem: http://support.apple.com/kb/TA47850?viewlocale=en_US&locale=en_US Although it's an old article, it could possibly still apply, just have to try...