6 ms·

Live Streaming a Macintosh Plus

104 points by ecliptik 5y ago

yjftsjthsd-h 5y ago
Tangentially related: This uses a HDMI-to-USB video capture device, which is great (I did not know they were that cheap and have ordered 2:]), but does anyone happen to know of a cheap VGA-to-USB capture device? I'm having a surprising amount of trouble turning one up, for all that I would expect them to be at least as easy to procure. (I'm interested in hacking together cheap lights out management for an assortment of oldish computers; emulating USB input devices with a microcontroller is easy, so if I could get VGA I could trivially remote control 10-15 years of computers. Unfortunately, somehow all of the "Pi LoM" projects I can find require HDMI.)
- kotaKat 5y ago
  I've found good use of VGA to HDMI adapters combined with the HDMI to USB dongle. I know it's not an ideal solution, but it was the quickest and dirtiest solution I could come up with in a pinch. Walmart[1] seems to have the VGA to HDMI adapters tucked in with the video stuff. I've also noticed they now carry the HDMI-USB adapters, branded Vivitar, for roughly $20 in the camera gear. [1] I live in rural NY where Amazon Prime is impractical (4-5 day shipping via Prime) and my only local retail is a Walmart, so I keep an eye on what's local to me if only because if I need it ASAP...
- headass 5y ago
  hdmi to vga adaptor? i don’t think you can just do vga to usb as it’s analog to digital isn’t it?
  - AnIdiotOnTheNet 5y ago
    You can do composite to USB easily enough with a $10 adapter, no reason to believe VGA is fundamentally more difficult to capture. Well, not because it is analog anyway. The real difficulty is that there are ton of modes you'd have to be able to detect and support.
- yftsui 5y ago
  The HDMI to USB dongle (video encoder) usually is a wrapped MS2109 chip, you also want VGA to HDMI which is an ADC + HDMI transmitter, something like MS9282. I guess it would be difficult to find a dongle that happen to have both chips, so the easiest way would be get a VGA to HDMI and plug it to the HDMI to USB encoder.
- assttoasstmgr 5y ago
  Why would you not just use one of the dozens of KVM-over-IP devices on the market? Or if you want to run it over a USB connection look for a "crash cart" device. This is a solved problem space. There is no case in which you would save money by doing this, even if your time was worthless. If the PCs are old enough you'd probably want PS/2 rather than USB. For the same reason people do not build their own mobile phones.
  - hnlmorg 5y ago
    Not OP but the KVM-over-IP devices I've seen work on multicast and thus are pretty terrible for network performance unless you have managed switches with packet inspection. They also don't play well with many WiFi access points too. I've not seen any KVMs that work via unicast for < £100. Whereas you can easily get a HDMI capture device plus VGA to HDMI adapter for < £100. If you know of any KVMs that don't use multicast then I'd be interested to know because I've been looking to move my CCTV display.
  - yjftsjthsd-h 5y ago
    All the options I can immediately find seem to be hundreds of dollars and still usually need HDMI. Could you point me at a specific model or at least vendor I should be looking at?
    - assttoasstmgr 5y ago
      Lantronix makes some nice products with VGA and HTML5 interface. However they seem to have tripled in price and I wonder if this is due to supply & demand. (Remember remote KVM over IP is a server-grade product that likely deals in low volumes so the price will reflect that.)
- einr 5y ago
  The Epiphan AV.io HD is a thing, but it's not cheap... You might be able to find a used Epiphan VGA2USB for not much money.
- unfocussed_mike 5y ago
  Those dirt-cheap HDMI capture cards are surprisingly useful. There is a Raspberry Pi HDMI-to-CSI capture card now that presumably uses the same or similar chip: https://www.waveshare.com/wiki/HDMI_to_CSI_Adapter https://www.waveshare.com/wiki/HDMI_to_CSI_Adapter (The Pi Hut have it)
  - reaperducer 5y ago
    Those dirt-cheap HDMI capture cards are surprisingly useful. How good are they with respecting content protection flags? I've thought about getting one for a weekend project, but very occasionally my AppleTV lies to me that it can't play my own home videos because my TV doesn't support DRM. So I'm uneasy about buying a piece of gear only to find out later that it's flaky in the same way.
    - giantrobot 5y ago
      I would not trust them for any protected content. I have had good luck with going from a camcorder's HDMI out (using it as a fancy webcam) and output from a Raspberry Pi. Both are unencrypted signals. An AppleTV or likely even a PC's output will likely enforce encryption and I highly doubt HDMI capture will work then. But at ~$20 it's not an expensive experiment.
      - unfocussed_mike 5y ago
        Yeah -- I use one to get debug console access to a Raspberry Pi, and to show the output from a Nikon or Sony camera. Not tried to see what happens with my Mac Mini, but then I only ever used that with DVI monitors, and I don't think I ever tried e.g. DVD protected content.
    - monocasa 5y ago
      A lot of the HDMI 'splitters' (one source to many sinks) are also DRM strippers.
    - unfocussed_mike 5y ago
      Never tried that -- what sort of thing would you test if you had one?
- Nextgrid 5y ago
  Have a look at the device mentioned here if you can still find it: https://blog.benjojo.co.uk/post/userspace-usb-drivers https://blog.benjojo.co.uk/post/userspace-usb-drivers
- rz2k 5y ago
  Probably not what you mean, but you could use a USB logic analyzer. https://digilent.com/reference/test-and-measurement/digital-discovery/demos/decoding-vga-signals-with-logic-analyzer https://digilent.com/reference/test-and-measurement/digital-...
  - monocasa 5y ago
    Logic analyzers don't typically allow for continuous traces; they fill their memory pretty quickly. So you can only expect screen shots at best. Also, most logic analyzers don't work with VGA since it's an analog protocol.
JKCalhoun 5y ago
Very cool. I was excited to try it until I saw you have to tap into the CRT cable bundle inside the Mac case. Actually, I think I'm still excited to try it — I need to recap my old Mac Plus and might as well make the hardware mod then. (Debating whether to add a clean rear connector for the "video out" rather than the wires hanging out like in the article … it would require drilling a hole in the case.) I'm surprised those video wires did not need to be shielded. Flustered me would run a Mac emulator on modern hardware, capture the display that way. I know that's cheating though.
johndoe0815 5y ago
There were some hacks to connect an external (Hercules-compatible monochrome) monitor or a projector to a compact Mac (128/512/Plus) in the 1980s. Building such an adapter is described on p. 168/169 in https://vintageapple.org/macbooks/pdf/Macintosh_Repair_&_Upgrade_Secrets_1990.pdf https://vintageapple.org/macbooks/pdf/Macintosh_Repair_&_Upg... and there's a thread on a projector adapter at https://tinkerdifferent.com/threads/compact-mac-video-adapter.462/ https://tinkerdifferent.com/threads/compact-mac-video-adapte... Great to see that this approach is still useful today!
- johnklos 5y ago
  Somebody was getting rid of a Macintosh Classic that had a broken neck on the display tube. I built it in to a small tower case that was common in the early '90s and connected it to a TTL monitor using a 74LS14, which I think I learned about from the "Macintosh Repair & Upgrade Secrets" book. We used to call those Hackintoshes back then ;)
  - drewzero1 5y ago
    Fascinating! I remember seeing somebody do something similar with a first-generation iMac in the 2000s. It was kind of like a DIY Mac Mini.
- matthewdgreen 5y ago
  Could you get color? The original Quickdraw APIs (from 128->Plus ROMs) all had library that supported a handful of primary colors, but I was never certain if there was any hardware (pre-Mac II) that could actually do anything with color.
  - johndoe0815 5y ago
    No, this just adjusted the video levels to TTL - and you had to adjust the frequencies of the monitor since the Hercules HSync/VSync frequencies were not exactly what the original Macs generated. The QuickDraw source code (https://computerhistory.org/blog/macpaint-and-quickdraw-source-code/ https://computerhistory.org/blog/macpaint-and-quickdraw-sour...) definitely has some color support, I think the CHM version source code is for an early version used in monochrome Macs (but there's no version number or date given).

104 points by ecliptik 5y ago

Tangentially related: This uses a HDMI-to-USB video capture device, which is great (I did not know they were that cheap and have ordered 2:]), but does anyone happen to know of a cheap VGA-to-USB capture device? I'm having a surprising amount of trouble turning one up, for all that I would expect them to be at least as easy to procure. (I'm interested in hacking together cheap lights out management for an assortment of oldish computers; emulating USB input devices with a microcontroller is easy, so if I could get VGA I could trivially remote control 10-15 years of computers. Unfortunately, somehow all of the "Pi LoM" projects I can find require HDMI.)

kotaKat 5y ago
I've found good use of VGA to HDMI adapters combined with the HDMI to USB dongle. I know it's not an ideal solution, but it was the quickest and dirtiest solution I could come up with in a pinch. Walmart[1] seems to have the VGA to HDMI adapters tucked in with the video stuff. I've also noticed they now carry the HDMI-USB adapters, branded Vivitar, for roughly $20 in the camera gear. [1] I live in rural NY where Amazon Prime is impractical (4-5 day shipping via Prime) and my only local retail is a Walmart, so I keep an eye on what's local to me if only because if I need it ASAP...
headass 5y ago
hdmi to vga adaptor? i don’t think you can just do vga to usb as it’s analog to digital isn’t it?
- AnIdiotOnTheNet 5y ago
  You can do composite to USB easily enough with a $10 adapter, no reason to believe VGA is fundamentally more difficult to capture. Well, not because it is analog anyway. The real difficulty is that there are ton of modes you'd have to be able to detect and support.
yftsui 5y ago
The HDMI to USB dongle (video encoder) usually is a wrapped MS2109 chip, you also want VGA to HDMI which is an ADC + HDMI transmitter, something like MS9282. I guess it would be difficult to find a dongle that happen to have both chips, so the easiest way would be get a VGA to HDMI and plug it to the HDMI to USB encoder.
assttoasstmgr 5y ago
Why would you not just use one of the dozens of KVM-over-IP devices on the market? Or if you want to run it over a USB connection look for a "crash cart" device. This is a solved problem space. There is no case in which you would save money by doing this, even if your time was worthless. If the PCs are old enough you'd probably want PS/2 rather than USB. For the same reason people do not build their own mobile phones.
- hnlmorg 5y ago
  Not OP but the KVM-over-IP devices I've seen work on multicast and thus are pretty terrible for network performance unless you have managed switches with packet inspection. They also don't play well with many WiFi access points too. I've not seen any KVMs that work via unicast for < £100. Whereas you can easily get a HDMI capture device plus VGA to HDMI adapter for < £100. If you know of any KVMs that don't use multicast then I'd be interested to know because I've been looking to move my CCTV display.
- yjftsjthsd-h 5y ago
  All the options I can immediately find seem to be hundreds of dollars and still usually need HDMI. Could you point me at a specific model or at least vendor I should be looking at?
  - assttoasstmgr 5y ago
    Lantronix makes some nice products with VGA and HTML5 interface. However they seem to have tripled in price and I wonder if this is due to supply & demand. (Remember remote KVM over IP is a server-grade product that likely deals in low volumes so the price will reflect that.)
einr 5y ago
The Epiphan AV.io HD is a thing, but it's not cheap... You might be able to find a used Epiphan VGA2USB for not much money.
unfocussed_mike 5y ago
Those dirt-cheap HDMI capture cards are surprisingly useful. There is a Raspberry Pi HDMI-to-CSI capture card now that presumably uses the same or similar chip: https://www.waveshare.com/wiki/HDMI_to_CSI_Adapter https://www.waveshare.com/wiki/HDMI_to_CSI_Adapter (The Pi Hut have it)
- reaperducer 5y ago
  Those dirt-cheap HDMI capture cards are surprisingly useful. How good are they with respecting content protection flags? I've thought about getting one for a weekend project, but very occasionally my AppleTV lies to me that it can't play my own home videos because my TV doesn't support DRM. So I'm uneasy about buying a piece of gear only to find out later that it's flaky in the same way.
  - giantrobot 5y ago
    I would not trust them for any protected content. I have had good luck with going from a camcorder's HDMI out (using it as a fancy webcam) and output from a Raspberry Pi. Both are unencrypted signals. An AppleTV or likely even a PC's output will likely enforce encryption and I highly doubt HDMI capture will work then. But at ~$20 it's not an expensive experiment.
    - unfocussed_mike 5y ago
      Yeah -- I use one to get debug console access to a Raspberry Pi, and to show the output from a Nikon or Sony camera. Not tried to see what happens with my Mac Mini, but then I only ever used that with DVI monitors, and I don't think I ever tried e.g. DVD protected content.
  - monocasa 5y ago
    A lot of the HDMI 'splitters' (one source to many sinks) are also DRM strippers.
  - unfocussed_mike 5y ago
    Never tried that -- what sort of thing would you test if you had one?
Nextgrid 5y ago
Have a look at the device mentioned here if you can still find it: https://blog.benjojo.co.uk/post/userspace-usb-drivers https://blog.benjojo.co.uk/post/userspace-usb-drivers
rz2k 5y ago
Probably not what you mean, but you could use a USB logic analyzer. https://digilent.com/reference/test-and-measurement/digital-discovery/demos/decoding-vga-signals-with-logic-analyzer https://digilent.com/reference/test-and-measurement/digital-...
- monocasa 5y ago
  Logic analyzers don't typically allow for continuous traces; they fill their memory pretty quickly. So you can only expect screen shots at best. Also, most logic analyzers don't work with VGA since it's an analog protocol.

JKCalhoun 5y ago

Very cool. I was excited to try it until I saw you have to tap into the CRT cable bundle inside the Mac case. Actually, I think I'm still excited to try it — I need to recap my old Mac Plus and might as well make the hardware mod then. (Debating whether to add a clean rear connector for the "video out" rather than the wires hanging out like in the article … it would require drilling a hole in the case.) I'm surprised those video wires did not need to be shielded. Flustered me would run a Mac emulator on modern hardware, capture the display that way. I know that's cheating though.

johndoe0815 5y ago

There were some hacks to connect an external (Hercules-compatible monochrome) monitor or a projector to a compact Mac (128/512/Plus) in the 1980s. Building such an adapter is described on p. 168/169 in https://vintageapple.org/macbooks/pdf/Macintosh_Repair_&_Upgrade_Secrets_1990.pdf https://vintageapple.org/macbooks/pdf/Macintosh_Repair_&_Upg... and there's a thread on a projector adapter at https://tinkerdifferent.com/threads/compact-mac-video-adapter.462/ https://tinkerdifferent.com/threads/compact-mac-video-adapte... Great to see that this approach is still useful today!

johnklos 5y ago
Somebody was getting rid of a Macintosh Classic that had a broken neck on the display tube. I built it in to a small tower case that was common in the early '90s and connected it to a TTL monitor using a 74LS14, which I think I learned about from the "Macintosh Repair & Upgrade Secrets" book. We used to call those Hackintoshes back then ;)
- drewzero1 5y ago
  Fascinating! I remember seeing somebody do something similar with a first-generation iMac in the 2000s. It was kind of like a DIY Mac Mini.
matthewdgreen 5y ago
Could you get color? The original Quickdraw APIs (from 128->Plus ROMs) all had library that supported a handful of primary colors, but I was never certain if there was any hardware (pre-Mac II) that could actually do anything with color.
- johndoe0815 5y ago
  No, this just adjusted the video levels to TTL - and you had to adjust the frequencies of the monitor since the Hercules HSync/VSync frequencies were not exactly what the original Macs generated. The QuickDraw source code (https://computerhistory.org/blog/macpaint-and-quickdraw-source-code/ https://computerhistory.org/blog/macpaint-and-quickdraw-sour...) definitely has some color support, I think the CHM version source code is for an early version used in monochrome Macs (but there's no version number or date given).