Settings For Best Audio...

[1957Goldtop]

Right now, I’m using the current Apple TV 3 preset but would like to modify the Audio settings; On some discs, like concerts, I would like the audio to be as good as it was on the Blu Ray/DVD with no compression being applied by Handbrake.

What settings would get me the best audio?

Thanks!

[TedJ]

The current settings.

The ATV3 preset creates a stereo AAC track as the primary track and passes through the original AC3 track from DVD sources, or in the case of DTS/DTS-HD tracks it creates an AC3 track as that's all the ATV3 supports.

[1957Goldtop]

Thanks!

So how does the Apple TV know which track to use and can use switch tracks?

For example you said it makes a stereo track but then also has the original AC3 track (which would be a higher bit rate I believe and possibly in 5.1)... how does it know which track to use?

[TedJ]

You need to have a compatible AV receiver/amplifier. The ATV doesn't do anything with the AC3 audio except pass it through to your amp to decode.

[1957Goldtop]

Coming back to this...

I clearly don't know what's going between the ATV and the receiver. If I rip a bluray with Handbrake and it has multiple audio tracks, what is being sent to the receiver by the ATV? All of them, and the receiver decides which is best?

For example, this is how I have the audio configured when ripping:
https://dl.dropboxusercontent.com/u/742 ... eaudio.jpg

Does the ATV send all of those to the receiver?

Thanks!

[mduell]

Best configuration for ATV is 1st track 2ch AAC 2nd track 6ch AC3. ATV doesn't support DTS and doesn't like the tracks out of order.

[1957Goldtop]

So, based on my configuration above, should I skip the "pro logic II"?

I've been doing stereo and then pro logic II first and second. Then, I do all the other formats as passthrough. I figured I would add all of them in case the ATV ever did support DTS.

[BradleyS]

The "standard" configuration for AppleTV is AAC 160kbps followed by AC3 passthru. The AppleTV should automatically pick the AC3 if Dolby Digital is set to "Auto" or "On" in your preferences.

As far as mixdowns go, Pro Logic II is fine. It's the best of both worlds, in a sense. You get a regular, stereo signal that works on anything, and the extra surround channels are cleverly hidden in the stereo signal using frequencies too high for our ears to hear. It looks like stereo to just about anything, but if you set your receiver to Pro Logic II mode, voila... you have pretty decent surround sound. Not as good as discrete 5.1 AC3, but not bad, and at virtually zero cost to you. Leave it on Pro Logic II (which is stereo plus a hidden trick) unless you have a special reason to use only stereo.

Basically, use the AppleTV 3 preset!

Beware that a new AppleTV was just announced which also supports E-AC3 (Dolby Digital Plus) for up to 7.1 channels. Sadly, there is no digital optical out port, so all audio requires an HDMI TV/receiver. We obviously haven't got our hands on it just yet, so HandBrake has no preset for it.

[1957Goldtop]

The reason I was doing Stereo AND Dolby Pro Logic II is, my main receiver is a 2 channel stereo receiver. But, I want the audio channels there in case of future receivers that support AC3/DTS.

So, it sounds like I should actually skip the 2 channel stereo and just use Pro Logic II as the first track and then AC3 from there.

[BradleyS]

Yep. Pro Logic II is designed to be stereo to receivers that do not support the extra hidden channels. Having an extra stereo track is not necessary.

[1957Goldtop]

And one final question... When choosing which track is used to convert to Pro Logic II, which is best.

For example, I have a few option on one of my disc:

DTS-MA
DTS-HD HRA
DTS-ES
AC3 Dolby Digital EX

Since DTS-MA is the "best" should I use that one to convert to PLII?

[BradleyS]

In order of general quality:

• DTS-HD MA (lossless extension to DTS) or Dolby TrueHD (lossless, AC3 core is optional)
  DTS-HD HRA (lossy extension to DTS) or Dolby Digital Plus / E-AC3 (lossy extension to DD/AC3)
  DTS-ES (lossy extension to DTS) or Dolby Digital EX AC3 (lossy extension to DD/AC3)

HandBrake currently only reads the DTS "core" in DTS-HD MA (and I believe the others, too). While DTS-HD MA is lossless, HandBrake isn't using the lossless part. Currently, they're all about the same to HandBrake.

[1957Goldtop]

Thanks...

You mentioned the new Apple TV above. Obviously you have no insight into it, but would there really need to be a different preset for the new ATV? Seems like all the audio/video specs are the same.

I'd hate to think I'll need to redo all my blurays.

[nhyone]

Only if you want Dolby Digital Plus 7.1. Otherwise the audio formats are the same.

Video is a little different.

New:
H.264 video up to 1080p, 60 frames per second, High or Main Profile level 4.2 or lower
H.264 Baseline Profile level 3.0 or lower with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats


Old:
H.264 video up to 1080p, 30 frames per second, High or Main Profile level 4.0 or lower
Baseline Profile level 3.0 or lower with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats


Source for the new spec: http://www.apple.com/tv/specs/

[1957Goldtop]

What would going from level 4.0 to 4.2 gain?

[kpflugshaupt]

What would going from level 4.0 to 4.2 gain?

You can study the levels here: http://blog.mediacoderhq.com/h264-profiles-and-levels/

Basically, they're more like envelopes of features which a device supports (or doesn't). According to the site I linked to, going from 4.0 to 4.2 allows higher bit rates, more blocks per frame (whatever that means in practice), and higher resolutions and/or more frames per second.

For a source with given parameters that are covered by Level 4.0, Level 4.2 is most probably not going to bring anything new.

Best regards
Kaspar

[BradleyS]

The newly announced AppleTV's hardware decoder likely has a larger buffer and some other tweaks to make level 4.2 possible. While this enables 60 fps 1080p/2k, it also means that 24/25/30 fps 1080p is less restricted, notably at high quality (1080p @ RF 16-19) during complex scenes that would be vbv limited with the AppleTV 3 preset. So we'll probably adjust level and thus, vbv, to take advantage of the higher limits.

In layman's terms, the newly announced AppleTV can handle longer bursts of high bitrate video during complex scenes.

It's possible that the new device actually supports level > 4.2 but Apple hasn't announced it for internal reasons (secrecy around upcoming products/services). It will be trivial to find out whether AppleTV supports level 5.x video out of the box, and once iFixit or someone does a teardown to reveal the hardware decoder and other ICs, we'll have a better idea what the device truly supports in hardware.

4k requires level 5.1/5.2 depending on fps, though I imagine Apple would use HEVC, which isn't supported at all. The hardware could support it, but this is very easy to omit/disable in software.