Four Composite Input Solution...

[Dominik Müller]

dear all,
i am using OBS to stream live sport events.
for a specific discipline, i recieve four different SD Analog Camera Signals (Composite) and i have to bring it in to OBS.

know's anyone a solution how to solve this in a cheap way? has anyone some expirience with this cheap "video Grabbers" in OBS and can recommand me a brand/device? would it be possible to add four different usb Grabbers into OBS in parallel?

Osprey has a CaptureCard for about 1200.- US$ but i am looking for a cheaper solution for the moment.

thank you for some Feeback...
DOM

 

[dodgepong]

When you start getting into higher-level production, things start getting expensive. The most affordable quad-capture card I know about is the the Magewell Pro Capture Quad line, but you're still looking at shelling out $900 for that.

If you want to go bottom-barrel cheap, then you can see how your computer handles 4 Dazzles at a time, but I would never recommend anyone use a Dazzle.

 

[Dominik Müller]

thanks for the Feedback... the Magwell also don't capture Composite... same as all exept the Osprey. I am working on well paid Productions but i am looking for a composite quad device to test something for a special sport discipline. It is not so cool to buy such a card just to find out it is not what we are looking for...

 

[pantonvich]

I'm using a blackmagic quad sdi card about $500 and some cheap hdmi to sdi converters about $40 each - I'm running my cameria's about 500ft via the sdi cable.

 

[dodgepong]

He is capturing SD, not SDI.

Getting a set of upscalers is another solution, but that is also expensive. I think the best bet is to just get 4 composite capture cards rather than a single card with 4 inputs.

 

[pantonvich]

I wasn't clear - finding something like an "analog to sdi" and going to a "sdi input card". Something like this but cheaper (I'm new at this and might be completely off base):
https://www.bhphotovideo.com/c/prod...2digital_a_to_d_hd_sd_sdi_mini_converter.html

 

[dodgepong]

That is still not what OP needs, and even if it were, it doesn't fit in OP's budget restrictions.

 

[pantonvich]

Please don't think that I'm trying to beat a dead horse but I would like to understand.

The device I linked to has a spec that says: Input: "SD component (Betacam, EBU-N10), composite, ".

Is that not the same as "SD Analog Camera Signals (Composite) "?

I clearly understand that what I linked to was outside the budget - but often one can find much cheaper options once you find an item that works.

thanks

 

[dodgepong]

This is an SDI cable: https://www.bhphotovideo.com/images/images1000x1000/pearstone_sdi_1025_25_bnc_to_bnc_884245.jpg

You can get SDI cables in Standard Definition (SD) or High Definition (HD). These are referred to as SD-SDI or HD-SDI. They are found on professional-grade cameras and video equipment. Anything involving SDI is always very expensive, because the people who use it are large production companies, usually.

This is a Standard Definition composite (RCA) cable: https://upload.wikimedia.org/wikipe...eo-cable.jpg/1200px-Composite-video-cable.jpg

You would typically find these on many consumer-grade electronics from several years ago. They are usually paired with Red and White A/V RCA cables, like so: https://upload.wikimedia.org/wikipe...posite-cables.jpg/1200px-Composite-cables.jpg

The latter is what OP needs: some sort of card to capture card specifically for composite video. For something really cheap, the AVerMedia c039 isn't bad: https://www.amazon.com/AVerMedia-Definition-Composite-Cyberlink-C039/dp/B00603S1OS

 

[pantonvich]

thanks - that was helpful - sorry about hijacking the tread

 

[Octapoo]

A friend recently used one of those cheap USB grabbers (like $4 or whatever) with OBS and it apparently worked great for his purpose of recording an old VHS video. The problem with USB though is that one video device can saturate that whole USB bus, meaning that you can't attach two devices to the same bus. My motherboard has 3 or 4 buses for its many USB ports, so I could probably use a bunch of those devices if I had to, I'd just have to be careful about which ports I plug them into in order to get them all to work at once. Extra USB buses via an add-on card might help in this case.

However, I don't have to do that because I have a PCI card from eBay that captures 4 SD signals at once. It only cost me $8.

It wasn't easy to find. First of all, there are a lot of cards with 4 inputs that are capable of capturing only 1 input at a time, and sorting them out isn't easy. One trick is that the one-input-at-a-time cards are often listed as 30 or 60 FPS, and the all-four-at-once cards are often listed as 120 or 240 FPS, with this ridiculous terminology originating from surveillance camera recorders I believe, but not all of the listings are clear and some sellers don't even know what they have.

So I just looked for one that had four decoder chips on it, a chip supported in Linux, and for $8 I gambled on it probably working in Linux, and lucky me it did once I figured out the right option for the bttv driver.

 

[dodgepong]

Do you happen to know the name/brand?

 

[Octapoo]

No idea, but I took some pictures if you want to try to figure it out:



Never used this image host before. Hopefully it works.

Anyway, as you can see it has just 1 composite input and 4 S-Video inputs. I bought it assuming it would be easy to connect composite to S-Video, but its not. I ended up finding the datasheet for the Conexant Fusion 878A to find the pin for the composite input, which I found was connected to a 0 Ohm resistor on the other 3 chips. So I removed that resistor, added a 75 ohm resistor for termination, and some very thin wire turned into a twisted pair to RCA connectors mounted elsewhere in my case. (Obviously this is a photo of a spare card. I bought more, being unsure if I'd ever find such a thing again.)

"lspci -vvv" has this to say about each of the four video chips:

05:08.0 Multimedia video controller: Brooktree Corporation Bt878 Video Capture (rev 11)
Subsystem: iTuner Spectra8 CardA Input0
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 32 (4000ns min, 10000ns max)
Interrupt: pin A routed to IRQ 21
Region 0: Memory at fdcff000 (32-bit, prefetchable) [size=4K]
Capabilities: [44] Vital Product Data
No end tag found
Capabilities: [4c] Power Management version 2
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Kernel driver in use: bttv
Kernel modules: bttv

05:08.1 Multimedia controller: Brooktree Corporation Bt878 Audio Capture (rev 11)
Subsystem: iTuner Bt878 Audio Capture
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 32 (1000ns min, 63750ns max)
Interrupt: pin A routed to IRQ 7
Region 0: Memory at fdcfe000 (32-bit, prefetchable) [size=4K]
Capabilities: [44] Vital Product Data
No end tag found
Capabilities: [4c] Power Management version 2
Flags: PMEClk- DSI+ D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-

...and this to say about the bridge connecting them all to the PCI bus:

04:07.0 PCI bridge: Hint Corp HB6 Universal PCI-PCI bridge (non-transparent mode) (rev 11) (prog-if 00 [Normal decode])
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 32
Bus: primary=04, secondary=05, subordinate=05, sec-latency=32
I/O behind bridge: 0000a000-0000afff
Memory behind bridge: fdd00000-fddfffff
Prefetchable memory behind bridge: fdc00000-fdcfffff
Secondary status: 66MHz- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort+ <SERR- <PERR-
BridgeCtl: Parity- SERR- NoISA- VGA- MAbort- >Reset- FastB2B-
PriDiscTmr- SecDiscTmr- DiscTmrStat- DiscTmrSERREn-
Capabilities: [80] Power Management version 2
Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1+,D2+,D3hot+,D3cold+)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Bridge: PM- B3+
Capabilities: [90] CompactPCI hot-swap <?>
Kernel modules: shpchp

It basically saturates the PCI bus capturing four streams in 16-bit color, but can do 24-bit color for 3 or less. Thus using more than one card is basically pointless unless you're going to capture in monochrome. It doesn't offer any compressed formats.

Driver loads with this: modprobe bttv card=3,3,3,3
The inputs are out-of-order, e.g. to set it to composite input, you have to set it to what V4L2 thinks is S-Video input.

 

[dodgepong]

Very interesting. I tried some Googling but came up empty. I did find this, though, which sort of does the trick, sans audio: https://www.aliexpress.com/item/201...00839517.html?spm=2114.search0302.4.10.s060HJ

 

[Octapoo]

I haven't seen a USB one that will actually capture all four channels at once, so I searched for "STK1160" to find more information about it, and found this:

https://www.linuxtv.org/wiki/index.php/Stk1160_based_USB_2.0_video_and_audio_capture_devices

There it says "capturing is possible from only one input at a time."

So I would just get four of these:

http://www.ebay.com/itm/Hot-Sale-Ea...-Converter-Capture-Card-Adapter-/272781773111

Again, they'll have to be plugged into different USB buses, as 640x480 YUYV needs 18.4 MB/s and a single USB 2.0 bus has only 35 MB/s of bandwidth. So putting two or more on the same bus won't work. To sort that out, you plug one in, get it capturing, then plug in a second one and try to get it to capture too. If it won't, it is on the same bus as the first, and so unplug it and try a different port. Then with those two capturing, try to plug in a third. If you're lucky your computer will have four USB buses. If not, you can maybe add more via unused USB ports on your motherboard (10-pin header connectors meant to attach cables from drive bay panels with additional USB ports), or via add-on USB cards.

This bus limitation could be overcome if a dongle offered MJPEG encoding, or any compressed encoding, but I have yet to see one that does.

 

[Boildown]

You need one of these: http://www.ebay.com/itm/251894427315 with the accessories (you'd need the breakout cables). Or the VisionSD4+1S model. But unfortunately I can't find one on Ebay atm at a reasonable price, you can get one new for far less than they're asking but still more than a grand. They sometimes appear on Ebay at significantly less, you might keep your eye out for it.

It would be more of a science fair project, but you could get two RGB-Pro2s, they need PCI slots, not PCIe, and you'd need to convert component to VGA-style RGB inputs (you can find adapters easily enough). https://www.datapath.co.uk/images/manuals/past-manuals/VisionRGB-PRO_capture_card_user_manual.pdf on Amazon pretty cheap here: https://www.amazon.com/gp/offer-listing/B00BSYFOCQ , can also find on Ebay, but make sure you get a RGB-Pro2 instead of a Pro1.

 

[Octapoo]

I had to remove my capture card from my computer, so here's a picture:



Hoping to replace it, I ordered a USB EasyCap device. The one I got does hardware MJPEG compression, so I ordered a few more, but unfortunately they still have to be connected to separate USB buses to work simultaneously.

I don't know why this is, but what I've read on the internet leads me to believe that the problem is that the devices are able to reserve bandwidth on the USB bus, and these dongles just reserve far more bandwidth than is actually needed for their MJPEG-encoded frames. So when I try to use a second one, even though the bandwidth exists for both to work at once, the bandwidth is reserved and so the second one isn't allowed to work.