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Deconstructing the home theater pre-processor - Page 2

post #31 of 52
Thread Starter 
Quote:
Originally Posted by amirm View Post

Protected audio path is a PC concept so it doesn't apply to such a piece of hardware. I think what you mean is that unprotected digital outputs are restricted in resolution which is correct. HDCP rules require that digital outputs be no better than 16/48. This device claims to output 96 KHz. Two things are possible: 1) it is violating the HDCP license agreement and you would hope that they are too small for anyone to notice and force them to change or 2) it only puts out 96 Khz if you feed it non-copy protected content over HDMI which in your application means this won't work.

I would contact them and ask.

Thanks for the correction on PAP. I will shoot them an email and see what they say. However at this point my interest in the HTPC thing is really only for blu ray playback and to investigate the capabilities of the platform for audio DSP. I don't use other sources in my theater at this point. I have the suspicion it would be excessively complex to try and integrate external sources and not something anyone rather than the most dedicated would want to undertake.
post #32 of 52
Quote:
Originally Posted by Nyal Mellor View Post

That's one of my key questions too. Certainly there are a lot of places the signal could get modified or changed. The only real way to know would be to test. How on earth do you test video bit perfect, if such a concept even exists??!

Yeah - not sure how to test... Maybe however the Secrets site tests the HDMI output in their Blu Ray reviews. They have some piece of test gear they said was uber expensive. It was detailed back in their Oppo 93 review I think. Maybe that same gear could just test the HDMI output of a PC using Jriver?

Perhaps they would want to team up with you to test the output of whatever you build once you deem it stable and close to complete....
post #33 of 52
I guess I don't understand the project yet.

It sounds like this will be an HTPC with an advanced audio processor built in? I thought it would be more like a hardware audio processor yet run on a PC platform. IOW, HDMI, AES/SPDIF, and analog inputs and AES/SPDIF and analog audio outputs. I can see where HDCP would be a problem in that nobody I am aware of makes an HDCP capture card with an open SDK.

I guess though if your media is DVD/BluRay or a media server this could work.
post #34 of 52
Thread Starter 
Quote:
Originally Posted by Glimmie View Post

I guess I don't understand the project yet.

It sounds like this will be an HTPC with an advanced audio processor built in? I thought it would be more like a hardware audio processor yet run on a PC platform. IOW, HDMI, AES/SPDIF, and analog inputs and AES/SPDIF and analog audio outputs. I can see where HDCP would be a problem in that nobody I am aware of makes an HDCP capture card with an open SDK.

I guess though if your media is DVD/BluRay or a media server this could work.

Yep HTPC with audio / video DSP then output to external DACs.
post #35 of 52
Thread Starter 
Quote:
Originally Posted by Nyal Mellor View Post

Thanks for the correction on PAP. I will shoot them an email and see what they say. However at this point my interest in the HTPC thing is really only for blu ray playback and to investigate the capabilities of the platform for audio DSP. I don't use other sources in my theater at this point. I have the suspicion it would be excessively complex to try and integrate external sources and not something anyone rather than the most dedicated would want to undertake.

Quoting myself now. Arvus Group, manufacturer of the device gave me a call back. Apparently the device passes whatever bit rate is on the input HDMI side with no HDCP restrictions.
post #36 of 52
Quote:
Originally Posted by Nyal Mellor View Post

- difficulty (impossibility?) of using non-PC sources such as game consoles
- lack of availability of surround post-processing algorithms such as DTS Neo X
- ongoing ease of use and maintenance overhead issues due to use of Windows as OS

If you have inputs on your ASIO device you can route audio from a game console, etc. through JRiver using its ASIO line input. Did you get any mic pres on the Metric Halo that could be used for inputs?

You can purchase DST Neural UpMix and use it as a VST plugin if you want to use DTS's algorithms in real time for upmixing up to 7.1. Unfortunately it currently doesn't upmix to 12 channels like NEO X.
post #37 of 52
Thread Starter 
Quote:
Originally Posted by desertdome View Post

If you have inputs on your ASIO device you can route audio from a game console, etc. through JRiver using its ASIO line input. Did you get any mic pres on the Metric Halo that could be used for inputs?.

That's very true. The Metric Halo has 8 ins, no mic pres on my unit though, although you can get that as an option. You could route HDMI from other sources direct to a display, video processor or switch and audio into the HTPC for processing.
Quote:
Originally Posted by desertdome View Post

You can purchase DST Neural UpMix and use it as a VST plugin if you want to use DTS's algorithms in real time for upmixing up to 7.1. Unfortunately it currently doesn't upmix to 12 channels like NEO X.

Looks like that is for Pro Tools only? JRiver has it's onboard JRSS upmix algorithm. Not sure how that compares to DTS.
post #38 of 52
Wow... Nice work OP
post #39 of 52
Quote:
Originally Posted by Nyal Mellor View Post

Looks like that is for Pro Tools only? JRiver has it's onboard JRSS upmix algorithm. Not sure how that compares to DTS.
It says that there is a VST Plugin, and JRiver has support for those.
post #40 of 52
OK Nyal,

This is now a rather old thread and so I hope you get update notifications via your e-mail.

Are you still running JRiver in your HTPC and assuming you are still doing so, are you happy with it?
post #41 of 52
Thread Starter 
Yes still running JRiver, and still very happy with it!
post #42 of 52
Nyal, did you try any room correction yet on you home theatre pre-pro, like Dirac?
post #43 of 52
Thread Starter 
Quote:
Originally Posted by sdurani View Post

Nyal, did you try any room correction yet on you home theatre pre-pro, like Dirac?
Why yes, I have "Acoustic Frontiers" parametric EQ to deal with room issues not dealt with through acoustic treatment. Hand dialed by yours truly!

Haven't tried third party EQ yet. Have had a good report on Dirac from a client with a very high end stereo setup so am keen to give it a try. Just need to find time!
post #44 of 52
Quote:
Originally Posted by Nyal Mellor View Post

Why yes, I have "Acoustic Frontiers" parametric EQ to deal with room issues not dealt with through acoustic treatment. Hand dialed by yours truly!
AFPEQ, must be a favourite brand in your office.

Is the PEQ built into your HTPC or an external box?
Quote:
Originally Posted by Nyal Mellor View Post

Haven't tried third party EQ yet. Have had a good report on Dirac from a client with a very high end stereo setup so am keen to give it a try. Just need to find time!
No rush, just curiosity on my part.

As I mentioned when you started this thread, I'm following your blog entries about your HTPC because I'm curious to see if it can be done without the HTPC becoming a hobby unto itself (as I've seen all too often).
post #45 of 52
Thread Starter 
Quote:
Originally Posted by sdurani View Post

AFPEQ, must be a favourite brand in your office.

Is the PEQ built into your HTPC or an external box?
No rush, just curiosity on my part.

As I mentioned when you started this thread, I'm following your blog entries about your HTPC because I'm curious to see if it can be done without the HTPC becoming a hobby unto itself (as I've seen all too often).

The PEQ is in JRiver, full details in the article linked on first post.

The lack of updates means it is working great. There's a few niggles but no show stoppers.
post #46 of 52
I can add that Dirac in my HTPC with Lynx2b works EXCELLENT. Currently doing 2.1 and Jriver takes care of crossover between mains and sub, Works 100%.
post #47 of 52
Quote:
Originally Posted by CHA View Post

I can add that Dirac in my HTPC with Lynx2b works EXCELLENT. Currently doing 2.1 and Jriver takes care of crossover between mains and sub, Works 100%.

What version of windows are you running?
post #48 of 52
I'm running W7 Ultimate 32-bit for now. Will try W8.1 soon.
post #49 of 52
Quote:
Originally Posted by CHA View Post

I'm running W7 Ultimate 32-bit for now. Will try W8.1 soon.

Keep me posted. I had Dirac up and running on W7 and never got it to work on W8.
post #50 of 52

i think so,All of my audio disc are already ripped. Blu-ray seems like a bit of a hassle, because of the space requirements

os9n8Q

post #51 of 52
Hey Nyal I was going back through your article and noticed that you set the Intel graphics to output 1080p 60. Did you intentionally not use its ~24hz setting due to the current issues around the chipset not outputting the exact 23.xxx that is needed for that setting, or did you just not feel it was needed?

I used to use HTPC for Blu Ray playback with TMT3, 5, etc, but got fed up with wanting my source to output the exact 23.xxx hz signal needed and went back to my Oppo playing ISO files. I love the jukebox and other features the HTPC has but couldn't convince myself to give up the exacting nature of a quality standalone.

So my two issues were the 24hz playback and also trying to figure out how to get the PC to "leave the video signal alone" as best as I could. Obviously the PC has to output some level of gamma, brightness, etc that is set in the driver. How did you decide where to leave those? Just leave them at default and calibrate at the projector (or Lumagen, etc, if used), hoping that the native settings done crush blacks, clip whites, etc? I know early on in the HTPC days one would have to fiddle with the native settings of the graphics card app to get BTB or WTW to pass, regardless of the "pc level / video level" settings. I think that has been largely fixed these days.

Thoughts?
post #52 of 52
Thread Starter 
Quote:
Originally Posted by hifiaudio2 View Post

Hey Nyal I was going back through your article and noticed that you set the Intel graphics to output 1080p 60. Did you intentionally not use its ~24hz setting due to the current issues around the chipset not outputting the exact 23.xxx that is needed for that setting, or did you just not feel it was needed?

I used to use HTPC for Blu Ray playback with TMT3, 5, etc, but got fed up with wanting my source to output the exact 23.xxx hz signal needed and went back to my Oppo playing ISO files. I love the jukebox and other features the HTPC has but couldn't convince myself to give up the exacting nature of a quality standalone.

So my two issues were the 24hz playback and also trying to figure out how to get the PC to "leave the video signal alone" as best as I could. Obviously the PC has to output some level of gamma, brightness, etc that is set in the driver. How did you decide where to leave those? Just leave them at default and calibrate at the projector (or Lumagen, etc, if used), hoping that the native settings done crush blacks, clip whites, etc? I know early on in the HTPC days one would have to fiddle with the native settings of the graphics card app to get BTB or WTW to pass, regardless of the "pc level / video level" settings. I think that has been largely fixed these days.

Thoughts?

Actually 60Hz was set to reduce rainbow effect from my single chip DLP.

After some experimentation it's clear, however, that 24Hz output has smoother motion and things look more natural that way, so I went back to 24Hz.

I did notice some frame drop with 24Hz, I believe due to the issue you say about not outputting 23.xxx however with videoclock on in Jriver the issue goes away.

Video calibration of the system I did not cover in that blog post but it was a bit of a biatch. Key thing is to get some usable test patterns onto the HTPC so you can see what is going on with regards to black level, white clipping etc. I bypassed all the driver 'enhancements'. I have it setup so JRiver outputs 0-255 and this is squashed down by the video card to 16-235. I played around with 0-255 levels to the projector but it was doing some strange things at 0-255 so I went back to 16-235.

Post calibration (all adjustments done in Lumagen) it looks fantastic with my SIM2s.
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