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Discussion Starter · #1 ·
I did search some reasonable amount of time but couldn't eventually come up with a conclusive answer. According to this thread stanger89 states that some m-audio comes close to what i'd like to do and for other reasons it seems impractical to decode external sources.


My setup is a RME9632 with 4chn analog extension board for a total of 6 analog 24/192 outputs.


I like to setup 2 htpc, one audio pre/pro/jukebox, the other for video pre/pro/jukebox (maybe holo3d input for add. external gear).


Now I'd like to have the audio part on the video-pre simple (and vice versa), and like to output just spdif bitstreams to the audio pre, which would decode (software?) in realtime for analog output to the amps.


Did I miss a major point or can that be done? I'd love it since it would ease the complete setup from both hardware and software point of view. There will be a dedicated server (3. machine) with scalable Raid5 storage for media and client OS, aiming to have all clients diskless, with either Gigabyte I-Ram (local os on kinda solid state ramdisk) or with some server soft Venturecom BXP with remote-boot...


Stanger89? Anybody? Pleeease, there must be a way to decode external bitstreams, although I don't expect to have it hardware decoded on the RME (this is clear).


elektrip.
 

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Some Creative cards have hardware DD decoding for external sources. But, if you have an RME you're not going to be satisfied with the sound from Creative.


I've searched before and have not been able to find anyone with a software solution. Most cards can't even recognize AC3 input on SPDIF.


Maybe the Delta 1010 could be used if you decoded in the Video computer and used the 1010 for pass through. I don't know if you could easily control the volume in that configuration with the 1010.


To summarize, stranger89 is right.
 

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That and input switching are basically the two missing pieces that prevent a PC from being a practical replacement for a Pre-pro.
 

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Discussion Starter · #4 ·
OK looks like it will be an all-in-one htpc with internal playing and decoding.

Input switching could be easily done with the RME. Just trigger a mixer preset.

And yeah, right guessed, I don't like creative (audigy) products unless used for a game station.


So far, I'll probably go with a RME Fireface 800 external solution for this customers project and keep the pci/pci-e for the video part.


THX guys.

elektrip.
 

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If I could ask a question? I have a M-audio 1010. Is my sound card doing the decoding of the multichannel signal, or is the CODEC (AC3Filter, WinDVD etc.) that I've loaded on my PC doing the coding? ANd if if is the CODEC, what types of CODECS are used in the High End AV Receivers like Denon, Sondy etc. It seems that there are some pretty talented open source programmers out there that could write some pretty comparable CODECs. While AC3Filter is good, are there better ones out there to be used and is there code to be modified?
 

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The decoding is done in software. And the issue is no longer quality (it used to be, presumably due to "optimizations" for PC sound systems), the real issues are lack of input decoding, and lack of input switching.
 

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Discussion Starter · #7 ·
Ok I understand so far.


Is there any software in development in that direction, e.g. some kinda "middleware driver" that would catch digital inputs (or any routable wave-device), decode and post-process it (like bass/crossover/delays/volume/lipsync etc.) and route back to virtually any audio interface output like 8 analog outs? Due to DD/DTS/(THX?) licencing this couldn't be expected freeware, unless it uses already installed codecs. Even then, reasonably priced, such a versatile "htpc audio processor" could be a valuable problem solver in many cases I guess.


Rather sure something like this (or the dream of it) was discussed in some audio card shootout thread with M-Audio, RME and the like...but couldn't find these htpc pre/pro threads.


- Could graphedit help? Is it possible to route something like "toslink in->ac3filter->wave renderer (1,2,3...)"? (yeah I guess the filter graph would look more complex ;) In theory? Anyone tried?


- Some "enable trick" for software DVD players (windvd, powerdvd...) to accept decoding (and processing) of ext. SPDIF inputs, or even some plug-in for zoomplayer with any custom filters installed used as realtime processor.


Is it such a complex task to grab ac3 from inputs for real-time processing? The digital i/o is just another driver which could be accessed by directX?! Or is it some legal issue?

Yesterday I've read that it is possible to record ac3 live with some cards in some DAW configs. (not rip and offline transcode, and not using audigy or nforce2 tricks) so I guess the hardware should not be the issue, as long as it supports non-audio bitstream passthrough at the spdif input. Not even sure if RME can handle that, or if it's common or not for pro cards.


As mentioned, input switching should not be a problem, at least with the RME mixer, configured to load custom mixer profiles for that matter.


At least THAT can be automated with a simple keystroke send, where the faders can't be controlled other than with the mouse. I learnt the Fireface 800 Mixer can be Midi-controlled, at least the master volume when using standard midi, or using some mackie midi protocol to automate all features. I hope the HDSP9632 will just get the same mixer soft with midi control. Ok this is already far offtopic but another essential GO/NO GO decision point for me to go the htpc pre/pro way: Is it possible with Girder to send midi to an app, rather than listen to midi on the input side for which a plug-in exists (afaik) ?


Where do I miss the point? Someone enlight me please. Another problem is, right now I cannot even test it since I have no standalone DVD anymore (or any other spdif source) :)
 

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Quote:
Originally Posted by elektrip
Ok I understand so far.


Is there any software in development in that direction, e.g. some kinda "middleware driver" that would catch digital inputs (or any routable wave-device), decode and post-process it (like bass/crossover/delays/volume/lipsync etc.) and route back to virtually any audio interface output like 8 analog outs? Due to DD/DTS/(THX?) licencing this couldn't be expected freeware, unless it uses already installed codecs. Even then, reasonably priced, such a versatile "htpc audio processor" could be a valuable problem solver in many cases I guess.
As part of my work on DScaler5 I created a proof of concept for a filter to detect AC3 and send it to a decoder for further processing. In the form it is at the moment it is way too slow to be of any practical use but it does show how it can be done. I was planning to pick up on this again at some point but i'm concentrating ont e video side at the moment.


Any developers who want to pick this up and run with it are always welcome....


John
 

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"Some Creative cards have hardware DD decoding for external sources"


does this include the Audigy2 NX external USB box???? What is involved in "using" this feature? can it be utilized in Graphedit?


:confused:
 

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elektrip,


Regarding your request for shootouts/comparos between RME/M-Audio, and others, threads on avsforum exist. You need to search the archives, but you will find it.


If you are already thinking about 2-3 htpcs (expensive!), then you should be looking at RME & Lynx.


Good luck with your configuration!


- Steve O.
 

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Quote:
Originally Posted by jimwhite
"Some Creative cards have hardware DD decoding for external sources"


does this include the Audigy2 NX external USB box???? What is involved in "using" this feature? can it be utilized in Graphedit?


:confused:
The Extigy has hardward decoding, I don't know about other products.


"Dedicated Dolby Digital (AC-3) hardware DSP decoder with support of up to 24-bit I/O data format. Ability to decode Dolby Digital streams from optical, coaxial SPDIF input or host PC via USB connection"


I doubt it can be used in Graphedit.
 

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Discussion Starter · #13 ·
Quote:
Regarding your request for shootouts/comparos between RME/M-Audio, and others, threads on avsforum exist. You need to search the archives, but you will find it.
Yes I'm aware of these threads it was no request. I've mentioned to read some pre/pro info there too. Maybe I was not clear.

Quote:
If you are already thinking about 2-3 htpcs (expensive!), then you should be looking at RME & Lynx.
I already use RME interface (HDSP9632), but can't remote control the mixer :(

Building 2 clients makes only sense for me if I could splice up audio and video tasks (for flexibility/expandability on each). Which is not the case, so it will be 1 client for a/v playback, recording and preamp for outboard gear (audio only).


As it looks now, I'll use some ext. 8 chn. DAC (maybe even Lynx Aurora with Lynx AES16) or ext. audio interface, like the RME Fireface 800, to keep pci free for video and stuff.


If there was just a good control for the mixer...sigh, this breaks my nerves. Since it will be an integrated solution the pre/pro on both audio and video should reflect a good surround pre with ease of use and good sq (and foremost stable). This will be connected straight to a Sunfire Cinema Grand 7~400, so it must be verified that the signal can be limited in a reliable fashion.


The server will be separate raid5 box. I plan both boxes on Pentium M platform, not yet sure abot the client yet, who may run on amd x2
 

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elektrip,


I understand better where you are at with your setup. Integration/automation with a unified remote - I haven't reached that stage with my media room (yet) :)


Do you also know about the RME newgroup? It's listed off the manufacturer's website:


Server: news.x-networks.de

Forum: rme-audio.forum


There may be a chance you can find information about your specific hardware/software automation questions. I was able to find out how to get multi-channel sound working properly with my older RME card that way.


Good luck,


- Steve O.
 
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