OSSC Wolf Edition - Audio over HDMI

[becker]

Greetings folks

I have been quietly working on my own version of the OSSC (Open Source Scanline Converter). I have been inspired by what Marqs has accomplished. He continues to improve and upgrade the software. Marqs' project has come a long way. However, the hardware has remain unchanged for quiet some time. I wanted to contribute to furthering the project in some way. This is based off Marqs work. My day-job is a PCB designer. I do board layout and schematics every day. I have long wanted to make an interesting project board outside of work.

Here is a list of changes. The OSSC Wolf Edition is based off Marqs' OSSC DIY 1.5.
-Added multiple analog audio inputs. These get digitized and output through HDMI. Audio inputs come from SCART, RCA stereo, RCA jack for S/P-DIF, or headphone jack.
-Added a buffer to the VGA input (THS7327). The buffer has a LPF (low pass filter), adjustable schmitt triggers, and ESD (static shock) protection for the VGA port.
-Added dedicated ESD protection to the HDMI connector.
-The HDMI connector faces towards the back instead of the side. This makes the footprint space smaller since HDMI cable no longer has to loop around.
-SCART is the only connector on the side. The SCART cable elbow exits towards the back.
-Board size is 125x75mm (about 5x3 inches).

Rendering:

Blank board:

Built board rev1 front:

Built board rev1 back:


OSSC-W is not 100% finalized. First revision schematic and layout are done. Firmware and a housing have not been started. Schematic and firmware will be open source. The firmware will be a branch in git of the original OSSC.

Edit
I realize I came out of nowhere with this project. I am an unknown and several people got upset by lack of information.
I am a fan of Marqs' work but I do not know him. I asked him a few technical questions a few months ago when I was drawing the schematic. I complimented him for making the firmware and schematic public. I also complimented him for taking the time to respond to a couple technical inquires. We messaged maybe 6 times in 6 months. I do not have insider information or files.
I made the Wolf edition alone using just the schematic PDF. It's still a lot of work, but if you want to copy a circuit board, all you need is the schematic. The schematic has been public for a long time.

OSSC DIY v1.5 Schematic https://www.niksula.hut.fi/~mhiienka/os ... ematic.pdf

The most valuable, important and unique part of the OSSC is the firmware. The firmware is open-source.
https://github.com/marqs85/ossc

The firmware is the special sauce that makes off-the-shelf components (that anyone can buy) work together to make the OSSC.
The needed pieces to recreate the OSSC have been public for a long time.

[Thomago]

Seeing the HDMI Out, I presume this is only going to be offered in DIY form?

[Xyga]

- Does the buffer over VGA add lag ?
- What are schmitt triggers ?

- Would it be 100% compatible with Marqs-made firmware updates, or would the users of the W have to wait for your own version of it ?
- Any idea of the price of a fully assembled board already ? (like most people I definitely can't assemble/solder one myself)

[Galdelico]

Sounds awesome, huge thumbs up!

[PascalP]

Awesome!
I want to get a OSSC myself, but if this hits the market I would consider to buy this instead of the 'original'.

[neorichieb1971]

I'd want a comparison check done with the original OSSC first.

You can't ask for an interest check without giving a price. I'm assuming a 30-40% increase over the original OSSC?

This would have to work with Marq's f/w. I don't want a white elephant.

[leonk]

Congrats on tackling the biggest problem with the ossc!!

In the era of cheap hdmi unauthorized devices all over ebay and amazon; reproductions, everdrive, etc Not putting hdmi on the ossc is extremely conservative (some might say too extreme)

[Gered]

Very awesome, would love to see this get produced.

[becker]

Seeing the HDMI Out, I presume this is only going to be offered in DIY form?

The boards will come pre-assembled. There are 300 components and 1000+ solder joints. It is possible but impractical to be assembled by hand.
I think your real question is concerning HDMI licensing. I am going to build it and see what happens. If the consortium has time to shake down low quantity homebrew hardware then I can remove the audio processor. It then becomes similar to the original OSSC. The traces will already be there if the person wants to put the audio chip in themselves.

- Does the buffer over VGA add lag ?
- What are schmitt triggers ?

- Would it be 100% compatible with Marqs-made firmware updates, or would the users of the W have to wait for your own version of it ?
- Any idea of the price of a fully assembled board already ? (like most people I definitely can't assemble/solder one myself)

A primary goal from the beginning is to have as few differences in firmware as possible so it shares with Marqs firmware. Since two new chips are added (audio and VGA buffer), the firmware will be different. My hope is that it becomes a build option like the DIY audio board. When the code is compiled it can be flagged as -wolf so it grabs additional code needed to use the new chips. I am not a programmer and I only attempted this project because the firmware was open source. Integrating the wolf edition as a build option instead of a code branch is important to me.
The VGA buffer does not add lag. It is just a signal cleaner. You are thinking of a frame buffer like on the xrgb which would add lag. The wolf edition is still lag free like the original.
I probably should have left out some technical details like schmitt trigger. The original OSSC had these on the VGA H-Sync and V-sync. A schmitt trigger turns a sin wave into a square wave to try to make it less ambiguous as on or off. The buffer I picked for the VGA has integrated schmitt trigger for the sync lines instead of discrete components. Translation: the experience for end user is the same. It is only interesting because the rise and fall cutoffs can be manipulated in software.
On the original OSSC, there is a signal buffer on SCART and Component inputs, but not VGA. I think this decision was to save cost because VGA probably has the cleanest signal, or was expected to be used the least. Either way, now there is a buffer on VGA so all three video inputs have signal cleaners.

Congrats on tackling the biggest problem with the ossc!!

In the era of cheap hdmi unauthorized devices all over ebay and amazon; reproductions, everdrive, etc Not putting hdmi on the ossc is extremely conservative (some might say too extreme)

I felt like the hardware was due for a revision. The success probably took him by surprise. The original OSSC was humble kit intended to be a hand soldered that played safe with licenses. By humble I mean a beast that would take an entire weekend to solder.

[Xyga]

Thanks!

[RGB0b]

Please excuse me if this is a dumb question, but is it possible to add a switchable framebuffer to the output? I'll explain why...

My OSSC has been an absolutely essential tool in my setup and it's versatility has made all my console testing infinitely easier. That being said, it doesn't work on all TV's and capture cards. Being able to turn on a framebuffer that makes it compatible with "normal" 720p and 1080p signals would mean anyone who could trade a frame of lag for compatibility would now have a 100% compatible device. While I'd mostly use it with the framebuffer turned off for that near-zero lag solution, I'd turn it on for any game streaming through my "sensitive" capture card, as well as times I just want play on my big plasma that's currently only compatible with 480p mode.

Either way, as soon as a prototype is available, I'd love to buy one and do a full review.

[Xyga]

^ great idea

[bobrocks95]

I have all my retro consoles outputting through a VGA connector, so the adjustable sync buffer being added to that input sounds like a good idea to me! I'll keep an eye on this.

Please excuse me if this is a dumb question, but is it possible to add a switchable framebuffer to the output? I'll explain why...

My OSSC has been an absolutely essential tool in my setup and it's versatility has made all my console testing infinitely easier. That being said, it doesn't work on all TV's and capture cards. Being able to turn on a framebuffer that makes it compatible with "normal" 720p and 1080p signals would mean anyone who could trade a frame of lag for compatibility would now have a 100% compatible device. While I'd mostly use it with the framebuffer turned off for that near-zero lag solution, I'd turn it on for any game streaming through my "sensitive" capture card, as well as times I just want play on my big plasma that's currently only compatible with 480p mode.

Either way, as soon as a prototype is available, I'd love to buy one and do a full review.

He's not a software guy, so I think that's beyond the scope of this. That's more OSSC2 territory, since a lot more can be done with a framebuffer than just signal correction. Would certainly be nice though.

[orange808]

I'm in. Very welcome improvements.

[bobrocks95]

2 questions I thought about:

1) What are you doing for IR/remotes? I'm assuming you at least have an IR sensor on the board.

2) Will audio inputs be selectable separate from video inputs? For example, could I use the VGA connector and RCA audio in, or the SCART connector and headphone jack audio in?

[Thomago]

I think your real question is concerning HDMI licensing. I am going to build it and see what happens. If the consortium has time to shake down low quantity homebrew hardware then I can remove the audio processor. It then becomes similar to the original OSSC. The traces will already be there if the person wants to put the audio chip in themselves.

Yes yes, that's what I was going for. Sounds reasonable!

[Voultar]

It's the HDMI transmitter that gets you. Omitting audio or piping HDMI through a DVI port is moot.

[lettuce]

I would defiantly be up for one of these becker, put me done for one.

I know this is a long shot but an ideas of time frame for a first run, 6 months???

[CobraKing]

This is very interesting but have you reached out to marqs and BuckoA51? If anything marqs ought to be compensated for his solid work on the OSSC.

[bobrocks95]

This is very interesting but have you reached out to marqs and BuckoA51? If anything marqs ought to be compensated for his solid work on the OSSC.

The code is publicly available, depending on the licensing used the whole point is that people can freely modify it and offer their own versions.

[austin532]

So I'm curious as to why you added Composite but not S-video? Just about every major systems that supports composite also supports s-video.

[Ripthorn]

So I'm curious as to why you added Composite but not S-video? Just about every major systems that supports composite also supports s-video.

Is not composite. It's just coax audio.

[becker]

Please excuse me if this is a dumb question, but is it possible to add a switchable framebuffer to the output?

It's not a dumb question. You're just thinking ahead. This is beyond what I have planned. My understanding is that it would need RAM. Which then requires a larger FPGA because the current one does not have enough pins left over. Then it requires programming to use the RAM for a frame buffer.
This is well beyond my skills.

[becker]

This is very interesting but have you reached out to marqs and BuckoA51? If anything marqs ought to be compensated for his solid work on the OSSC.

Marqs has graciously given advice during devolopment and only asked that the open source license be honored.
I follow BuckoA51 's projects but I haven't written him before. I implimented audio differently than the DIY audio board. It does not use his work.
Both of these guys are very generous with their knowledge and open source projects.

[Guspaz]

Suggestion: optional video DAC for analog RGBHV output. This would allow the OSSC to be used on computer CRTs. I've seen a few people asking questions about if the OSSC will work on a CRT using an HDMI-to-VGA converter, and it'd be nice if that was either built-in, or was possible with a easy add-on.

[BuckoA51]

Markus and I have been discussing integrating the audio onto the main board for some time now, this would save quite a bit for customers who want it over the current system, which involves posting the OSSC to my subcontractor and having him fit the board, then forwarding it on to the customer. Of course, for people that don't need the audio upgrade there'd be an increased cost if we did simply integrate it, but probably not that big.

I personally would prefer to stick to DVI out, I think the connector is more robust and it's less likely to get pulled up for licensing violations (even though technically it still is in violation) but it's true nobody else's hobby project has been targeted yet.

Suggestion: optional video DAC for analog RGBHV output. This would allow the OSSC to be used on computer CRTs. I've seen a few people asking questions about if the OSSC will work on a CRT using an HDMI-to-VGA converter, and it'd be nice if that was either built-in, or was possible with a easy add-on.

I'd be against this personally, every little niche feature you add just bumps the cost up for people that will never use it.

This is very interesting but have you reached out to marqs and BuckoA51?

Indeed please do reach out to me I'd like to remain involved with worldwide distribution (looking at the possibility of moving out of UK post Brexit if necessary) and there's really no point us having lots of different versions of the OSSC competing with each other when we can get some economies of scale here.

[Guspaz]

I'd be against this personally, every little niche feature you add just bumps the cost up for people that will never use it.

That's the entire point of this, though, a new OSSC-like product that covers the use cases that the core OSSC does not. If people wanted the cheaper minimal solution, they'd just get the OSSC.

That's also why I suggested it being optional, so that it could be installed only if needed. I wouldn't think it would need any firmware changes to support such a thing since the digital signals are already available. It could be as simple as leaving the space on the board for the DAC chip and VGA output connector to be optionally populated, or it could be something like a pair of unpopulated pin headers that are for a DAC board to plug in.

[RGB0b]

Suggestion: optional video DAC for analog RGBHV output. This would allow the OSSC to be used on computer CRTs. I've seen a few people asking questions about if the OSSC will work on a CRT using an HDMI-to-VGA converter, and it'd be nice if that was either built-in, or was possible with a easy add-on.

I assume integrating that will actually add more cost then the $25 HDMI to VGA converters I've used that seem to work great with the OSSC. That being said, if enough people want it to justify a small run of production, why not? That's the beauty of open source, right? In this particular case, I think the cost of just buying the converter might be much cheaper in the long run.

Indeed please do reach out to me I'd like to remain involved with worldwide distribution (looking at the possibility of moving out of UK post Brexit if necessary)

Matt, you've got a great store and you do a lot of good for the community...but if you end up being the UK distributor of these, please, no more mailing lists. I get at LEAST 20 emails a week asking why people can't just pre-order one of these and ask why I'd so prominently feature a product on my website that no one can get. I understand why you did it for the first batch, but (as we discussed publicly on the podcast), you need to switch to a better model. I absolutely vote for you to be the UK distributor, but not the only distributor and in-stock or pre-order sales only.

there's really no point us having lots of different versions of the OSSC competing with each other when we can get some economies of scale here.

That's like saying "there's no point in having different types of cars". Having an open source project that people customize and make their own version is awesome. I totally understand if most people want one type though...and if that's the case, maybe do a bulk pre-order and get the price way down...but the thought of different versions the suit people's needs in different ways is very cool.

Marqs has graciously given advice during devolopment and only asked that the open source license be honored.
I follow BuckoA51 's projects but I haven't written him before. I implimented audio differently than the DIY audio board. It does not use his work.
Both of these guys are very generous with their knowledge and open source projects.

What exactly IS the open source license for the OSSC? I've been confused about that since day one. I was under the impression the software (firmware) is open source and the hardware is controlled by Markus. If the hardware is open source and you were allowed to open a new branch of development, why weren't others? I don't mean to single you out Becker (sorry), but I've introduced some people to Markus via email who were discouraged from making their own version. It's either closed source hardware and Markus chooses who he'd like to work with, or it's open source and anyone can do what they please with it. I understand keeping it closed until the first order was fulfilled and Matt gets his money back (and seriously, Matt DESERVED to make money from that...he took a huge risk with his own savings), but now that you've been allowed the design files, what's the real story?



So, I'll ask here publicly: Is the "Open Source Scan Converter" open source or not?




...as an FYI, cause I'm sure someone's going to say something: I don't sell anything on my website anymore and will never again. I do not profit at all from anything OSSC-related. I'm a huge fan of the project and Markus' work (and I guess yours too now Becker) and hope to continue to see it grow...but can SOMEONE please set the rules for this project?

[BuckoA51]

Matt, you've got a great store and you do a lot of good for the community...but if you end up being the UK distributor of these, please, no more mailing lists. I get at LEAST 20 emails a week asking why people can't just pre-order one of these and ask why I'd so prominently feature a product on my website that no one can get. I understand why you did it for the first batch, but (as we discussed publicly on the podcast), you need to switch to a better model. I absolutely vote for you to be the UK distributor, but not the only distributor and in-stock or pre-order sales only.

Genuinely don't see the problem some people have with mailing/waiting lists, surely it's a lot fairer than just putting stuff up for sale as/when you get it and letting it be a mad rush? Taking big lumps of cash for pre orders has tax implications (I have to declare it as something on my tax return after all) which could mean it gets taxed as profit when it's not, further pushing up costs and causing issues.

If I didn't have a waiting list you'd still be getting the same ranting e-mails from people because the units would still sell out, just like Marshall gets whined at because the N64 HDMI's are sold out, Deunan gets moaned at because GDEmu is always sold out... etc etc and so on.

That's like saying "there's no point in having different types of cars". Having an open source project that people customize and make their own version is awesome. I totally understand if most people want one type though...and if that's the case, maybe do a bulk pre-order and get the price way down...but the thought of different versions the suit people's needs in different ways is very cool.

Sort of, but for the numbers of units you're talking in this kind of niche market, making dozens of variations on the same thing just doesn't make sense. If you don't want SPDIF for instance, you might save $5 in components or something, but by making a batch of 100 without SPDIF and 400 with you lose out on economies of scale. Likewise with every little variation you do you have to go through prototyping, testing etc before it's safe to order a big batch.

[RGB0b]

https://www.trycelery.com/