Designing a HTPC with linux os and software decoding

[yugaaa]

Searching on the net for want of a software codec I came across an AVR offering by Trinnov from France .
From what I gathered , It seems that the AVR is designed with a linux OS and running software codecs for Dolby atmos , DTS -x and almost all the latest audio video formats .

The special features are that it can never be obsolete until atleast 20 years due to the processing being done on a PC and not on a DSP . It has 32 channels of decoding as well .

Any one with more info on this ? I am planning to start a group DIY effort based on the same because it needs a bit of coding skills and hardware skills . I will post later the flow chart on how to go about building one's own AVR .

 

[nipunkx]

Sounds very interesting:clapping:

 

[reignofchaos]

There are no decoders for DTS-HD and Dolby True HD in linux without resorting to hacks where you must explicitly dlopen windows libs and execute code. Unless these guys wrote their own decoder, it is highly unlikely that this is possible.

Also this is no different than decoding the format to LPCM on an HTPC and passing it over HDMI. The only benefit I see would be shorter traces as the PC board is directly connected to the DAC and preamp. If you care then its fine else save your money and move on.

 

[yugaaa]

There are no decoders for DTS-HD and Dolby True HD in linux without resorting to hacks where you must explicitly dlopen windows libs and execute code. Unless these guys wrote their own decoder, it is highly unlikely that this is possible.

Also this is no different than decoding the format to LPCM on an HTPC and passing it over HDMI. The only benefit I see would be shorter traces as the PC board is directly connected to the DAC and preamp. If you care then its fine else save your money and move on.

I did not understand your post .

I think there are Encoders /decoders licensed by Dolby , DTS to various manufacturers , production studios . While a decoder inside an AVR can decode formats , why would it not be possible in Linux .

The objective of this whole DIY idea is based on the fact that whenever there is a new format we do not have to discard our old boxes , incorporate remote controls and just a component swap would upgrade it to the latest AVR .

I do not think people would buy the type of AVR from Trinnov if it did not make sense , especially at that cost . It is a professional decoder and used by Cinemas as well .

Any HTPC can do decoding of formats .. that would not be the problem .Problem is Digital room calibration and correction , equalisation etc .
Incorporate remote controls , Network features , Wireless display functions and most importantly have atleast 16 channels of audio which are format selectable .

For example .. Atmos speaker placement is different from DTS -X . so the idea here is to have speakers wired using the 16 channels and then according to the format the speakers play .

It is just an idea . It does not necessarily have to be with LInux . Can also use windows . With A/V software decoding formats would not be a problem .

 

[superczar]

20 years in 20 generations for a PC
No matter what you do, there is zero likelihood that the codecs/formats in use 20 years from now will be software (or hardware) decodable by today's processors!

Think of the highest end consumer PC from 1996 and imagine that poor thing trying to decode let alone a 4K 10 bit HEVC but even a basic 720p h.264 file

 

[reignofchaos]

I did not understand your post .

I think there are Encoders /decoders licensed by Dolby , DTS to various manufacturers , production studios . While a decoder inside an AVR can decode formats , why would it not be possible in Linux .

The encoders can only be licensed if they exist. Unfortunately there are no known decoders for Linux :lol:. Also the algorithms themselves are proprietary and the folks who built the codecs would definitely not open source it for a few linux geeks.

The objective of this whole DIY idea is based on the fact that whenever there is a new format we do not have to discard our old boxes , incorporate remote controls and just a component swap would upgrade it to the latest AVR .

Not so easy - codecs are coming thick and fast of late. The life of a codec these days is 2-3 years.

I do not think people would buy the type of AVR from Trinnov if it did not make sense , especially at that cost . It is a professional decoder and used by Cinemas as well .

Any HTPC can do decoding of formats .. that would not be the problem .Problem is Digital room calibration and correction , equalisation etc .
Incorporate remote controls , Network features , Wireless display functions and most importantly have atleast 16 channels of audio which are format selectable .

Nope they can't as I mentioned earlier. They can bitstream to an external device but it is very very different from decoding. Decoders have hundreds of software patents and if someone reverse engineers them, they'll be hit with both DMCA and patent lawsuits.

 

[yugaaa]

20 years in 20 generations for a PC
No matter what you do, there is zero likelihood that the codecs/formats in use 20 years from now will be software (or hardware) decodable by today's processors!

Think of the highest end consumer PC from 1996 and imagine that poor thing trying to decode let alone a 4K 10 bit HEVC but even a basic 720p h.264 file

Well, you would be surprised with what they use in a studio to encode sound . It is a very old server with specialist hardware to encode . I look at it as a lan card . we have had so many versions .. yet the pci slot has been around for almost 20 years .

Even today motherboards come with pci slots and many industrial motherboards have 3-4 slots for specialist uses . Well, even if it does not last 20 years a good 10 years is enough . A concept when it comes as a modular implementation I am sure a graphics card , or the HDMI processing can be upgraded probably say after 5-6 years of use .For the past 20+ years we have seen home theater surround , then 5.1 , then dolby surround etc . What has been constant is 5 sound channels . Even today entry level AVR uses 5 channels + a sub woofer channel . In all practicality if one were to use good speakers capable of going really low , then the sub is not needed . Since satellites and entry level speakers cannot go low we have dedicated sub .

 

[yugaaa]

The encoders can only be licensed if they exist. Unfortunately there are no known decoders for Linux :lol:. Also the algorithms themselves are proprietary and the folks who built the codecs would definitely not open source it for a few linux geeks.


Not so easy - codecs are coming thick and fast of late. The life of a codec these days is 2-3 years.


Nope they can't as I mentioned earlier. They can bitstream to an external device but it is very very different from decoding. Decoders have hundreds of software patents and if someone reverse engineers them, they'll be hit with both DMCA and patent lawsuits.

If there are no known decoders for linux how does Trinnov manage ? How do all the other commercial AVR manufacturers manage ? I am sure none of them have any flavour of windows running .. lol . What we are missing is codec is different from formats . Yes , a format might contain a codec or quite a no. of them , but i do not think a codec contains a format . Atmos would be a format with extra surrounds . DTS-X would again be a format .. not a codec .

I am not talking about reverse engineering . I am talking about going open source route to lower costs . Probably we might have a sound card manufacturer come up with a DSP and software for decoding or even a graphics card . What use would be an invention without masses adopting or using the technology ?

 

[reignofchaos]

If there are no known decoders for linux how does Trinnov manage ? How do all the other commercial AVR manufacturers manage ? I am sure none of them have any flavour of windows running .. lol . What we are missing is codec is different from formats . Yes , a format might contain a codec or quite a no. of them , but i do not think a codec contains a format . Atmos would be a format with extra surrounds . DTS-X would again be a format .. not a codec .

DTS-HD is a codec so is Dolby TrueHD and further implementations and derivatives of it. What you refer to as format is a container like mkv or wav or avi. All various dts codecs will have either a .wav or .dts container and TrueHD normally comes in an ac3 container.

I do not know what and how Trinnov is doing but if you do have some concrete information like a whitepaper, i shall be glad to analyze.

Commercial manufacturers of AVRs use processor chips that have hardware decoders for these formats that is licensed from the company that created the codec. There are certain Blu-ray software players too that do this such as Cyberlink Powerdvd but that is closed software which again obtains a license from the original IP creator.

I am not talking about reverse engineering . I am talking about going open source route to lower costs . Probably we might have a sound card manufacturer come up with a DSP and software for decoding or even a graphics card . What use would be an invention without masses adopting or using the technology ?

I am not sure what will you open source? Will you write the decoder in software from scratch by reverse engineering? That is the only way to do it though it would not be strictly legal. Dolby and DTS charge royalty by the license and only give their decoding algorithm to large OEMs. Where will you get this from? Also since it's their IP, they would obviously not allow open source implementations to use their algorithms until their patent for the same runs out.

 

[regeHA]

The thing is formats are changing every 2-3 years... we've gone from DTS to DTS-HD to DTS:X (as well the Dolby variants) in our generation and we're not done yet... ditto for video from DVD to 720p to 1080p to 4K... and Japan is talking 8K transmission.

Unlikely anything will last 4-5 years... let alone 20 years.

More importantly h/w decoding is where its at and that's licensed only to OEMs. S/w decoding works, but is extremely inferior and will take a lot of CPU.

Take the example of HEVC/H.265. Most of the latest sub $100 Android sticks and TV boxes handle it, but most PCs I've seen struggle unless they are aided by powerful/latest GPU.

Of course s/w has its advantages... requires less updates compared to h/w and is also more flexible as it can support more formats out of the box, but like I said extremely inefficient especially for the latest formats.

Add in DRM, piracy, etc. and most will be limiting decoding to h/w and OEM vendors only going forward... at least that's how Sony wants to play the game.

 

[yugaaa]

The thing is formats are changing every 2-3 years... we've gone from DTS to DTS-HD to DTS:X (as well the Dolby variants) in our generation and we're not done yet... ditto for video from DVD to 720p to 1080p to 4K... and Japan is talking 8K transmission.

Unlikely anything will last 4-5 years... let alone 20 years.

More importantly h/w decoding is where its at and that's licensed only to OEMs. S/w decoding works, but is extremely inferior and will take a lot of CPU.

Take the example of HEVC/H.265. Most of the latest sub $100 Android sticks and TV boxes handle it, but most PCs I've seen struggle unless they are aided by powerful/latest GPU.

Of course s/w has its advantages... requires less updates compared to h/w and is also more flexible as it can support more formats out of the box, but like I said extremely inefficient especially for the latest formats.


On a motherboard with multiple pci-e slots the option of having a hardware based decoder is easy . Porting software for the decoder can also be done . Companies like AKM in the past have offered evaluation boards ,samples to try out .
As far as what I was able to make out from the Trinnov pictures , it has 8-16 channels of DAC on each board . It has a HDMI switcher and the whole integration is done with the help of USB . The motherboard seems to be a generic one and does not have any special slots . That is where the whole thing gets interesting . To control the whole setup a front end with display and remote capabilities seems to have been used . The mic used for configuration seems to be totally different and I personally have a feeling that the Trinnov can outclass the various formats that can be played with respect to other manufacturers .
Funny part is as we discuss about Home segment , Trinnov actually supplies the boxes to cinemas world wide . If they had any issues I am sure no one would risk an investment

 

[yugaaa]

I am not sure what will you open source? Will you write the decoder in software from scratch by reverse engineering? That is the only way to do it though it would not be strictly legal. Dolby and DTS charge royalty by the license and only give their decoding algorithm to large OEMs. Where will you get this from? Also since it's their IP, they would obviously not allow open source implementations to use their algorithms until their patent for the same runs out.

For a start , I found this piece of software .
DRC: Digital Room Correction
https://sourceforge.net/projects/brutefirdrc/?source=recommended
These are the basic room correction , equalisation software which I could search .
The possibilities are endless . Even a basic 2 channel stereo would benefit and sound much better and probably more accurate with a digitally calliberated EQ .These are just ideas floating , but I see a lot of potential . 2 channel audio box with automatic equalization as a source would be a huge success .

 

[reignofchaos]

For a start , I found this piece of software .
DRC: Digital Room Correction
https://sourceforge.net/projects/brutefirdrc/?source=recommended
These are the basic room correction , equalisation software which I could search .
The possibilities are endless . Even a basic 2 channel stereo would benefit and sound much better and probably more accurate with a digitally calliberated EQ .These are just ideas floating , but I see a lot of potential . 2 channel audio box with automatic equalization as a source would be a huge success .

How is room correction remotely related to decoding DTS HD and Dolby True HD? Sorry I do not follow.

 

[yugaaa]

How is room correction remotely related to decoding DTS HD and Dolby True HD? Sorry I do not follow.

Simple . As you rightly said DTS HD is a codec built into a format . DTS is a format . Dolby True HD is a codec . Dolby Atmos is a format .

Each format specifies levels , speaker placements , equalisation etc . So first step would be to start with room correction , levels right ?

Why would someone buy an AVR rather than buy a BD player and hook it to an amp and speakers ? Because there is room correction , distance correction etc . Please check the Mic of Trinnov

 

[humblebee]

The idea is good.
What you seem to be doing is looking for a way all through to the end. Maybe very very few people have done it. So it would be hard to see all the way.
The project that gets started is the one that progresses.
So, I encourage you to get started and believe in yourself.
At least you will reach somewhere if not all the way...
Maybe you will come up with your own solutions to small problems that hamper progress...

Now, as someone who has built an htpc on windows, I can offer some things...

With so many functions that you have in mind (remote, calibration etc), right now instead of diving deep into just one area, you might want to focus on playing the role if a system integrator...one who gathers individual solutions made by others and integrates them to work in a system. By this itself you will learn a lot. And this itself will take some time and its already quite a goal.

And then there will be the cost thing...

So why not first build a basic htpc and then in second version go for the full thing...

What an avr does is 3 things minimum

1) Decode formats - DTS, Dolby etc
2) DAC - of the streams in there - 6(5.1) or 8(7.1) or more
3) Amplification of those streams - so a separate amp for each stream.

To manage within budget, a media centre will do good...

It will do the media mgmt + playback + decode functions well. Additionally the headache of getting latest linux based codecs of dolby, dts etc plus integrating them into playback software will be handled by the media center.
Yes there are free codecs that have been reverse engineered for dolby, dts etc even for linux platform.

(I dont think there will be too much difference between software decode and hardware decode in terms of quality...data is not lost in a proper software decode esp if its a licenced one from dolby etc...what is missing is a good 7.1 channel dac)

So, the solution is known more or less...

1) Media Center for playback...I used Nero as it is cheap plus picture quality was good plus it uses licence from dolby etc. It didnt have support for 7.1 3 yrs back though. (Check its MediaHome software). Additionally it offers streaming music from android phone to pc via wifi ... that was good.

For linux check link... https://www.maketecheasier.com/media-center-linux/

2) ASUS Xonar DX for dac part...it has good quality and affordable 7.1 decoding. Additionally it has dolby conversion options...7.1 to 5.1 to 2.0 and reverse. Check ASUS Xonar D2X for similar DTS functions. But even nero can do them internally I suppose.

3) Amplification was combined with spkrs and I bought affordable 5.1 spkr set with built in amplification.

The problem i had was that remote control integration was hard and i was not satisfied with the solutions available then.

For individual pc components selection and case (very imp for the look...) check my detailed post here some time back....http://www.hifivision.com/home-thea...s-all-i-have-learnt-about-building-htpcs.html
Take your time to go through the complete guide...its quite detailed...and I had worked a lot on it....more than most guides on the internet....and it gives fundas...so its relevant even today

I hope you find this useful

Best wishes

(Addendum...720p h.265 uses 30% cpu on potplayer on my i3-3220 system. Audio decoding doesnt use much cpu resources. Video codecs come around once in a decade. So if you go for todays gen i5 system then it should easily last a decade...even for 4K h.265)