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Sort of related tangent, there were some attempts at copy-protection for VHS. Technology Connections has a good video [0] on "MacroVision" [1], which would mess

Sort of related tangent, there were some attempts at copy-protection for VHS. Technology Connections has a good video [0] on "MacroVision" [1], which would mess with the vertical-blanking signal in a way that wasn't particularly noticeable on playback, but would mess with VHS recording. There was also apparently another method which was just a straight up lie, called KTC, that claimed it was coated with a chemical that would destroy any VHS recorder attempting to record it. Here's a screenshot of the pre-video bumper warning, alerting you to "STOP RECORDING NOW" [2]. Also any RedLetterMedia fans may remember this from the "dog sitting" video in Wheel of the Worst #7 (around 35:00 in). It sounds like a phony technology, and it is. It's just a lie intended to scare away anyone attempting to record the tape. [0] https://www.youtube.com/watch?v=-VqsU1VK3mU https://www.youtube.com/watch?v=-VqsU1VK3mU [1] https://en.wikipedia.org/wiki/Analog_Protection_System https://en.wikipedia.org/wiki/Analog_Protection_System [2] https://company-bumpers.fandom.com/wiki/K.T.C._Warning_Screen https://company-bumpers.fandom.com/wiki/K.T.C._Warning_Scree...

Steve44 5y ago
> which would mess with the vertical-blanking signal in a way that wasn't particularly noticeable on playback, but would mess with VHS recording On a related note, one of the copy protection systems I put on some Sinclair Spectrum cassette games involved changing the baud rate part way through loading. It was over 35 years ago so the details are hazy, but I had a custom "master maker" to play the audio[1] and at a specific byte count would change the frequency. The mastering and duplication machines coped with it fine and the loader was written to expect it, but it threw out most home tape to tape systems for reasons I can't exactly remember. [1] These were usually recorded directly from the Spectrum onto 2 inch reel to reel tapes in a studio, that was then used as the master at the duplicators.
dylan604 5y ago
Macrovision only worked on VCRs with the Automatic Gain Control (AGC) enabled. It was super easy to defeat by disabling the AGC, or if you had more sophisticated equipment like a time base corrector (TBC) or similar. These dubs will still have the Macrovision as is, but it won't affect the recording's video signal. Using a standards coverter NTSC->PAL for example would completely remove the macrovision from the dub.
- LeoPanthera 5y ago
  You could buy macrovision strippers from high street stores for years, Radio Shack / Tandy was a good candidate, they were usually sold as "video enhancers" or "video stabilizers" or similar language.
  - dylan604 5y ago
    Right, those were the consumer names of time base correctors. Edit: https://en.wikipedia.org/wiki/Time_base_correction https://en.wikipedia.org/wiki/Time_base_correction
    - LeoPanthera 5y ago
      I don't think they were that advanced. The cheap consumer stuff would just use analogue circuitry to blank out the signal during the vertical blanking interval.
      - dylan604 5y ago
        It depends on the model. There were some that would allow one to adjust the contrast/chroma/etc. Of course it was all analog circuits, that's what made it all so accessible! Also, it probably wouldn't blank out the entire blanking as you'd lose CC or Teletext data. I forget the exact lines the macrovision appear on, but it was much higher than 17. We also used to embed ID codes in the blanking that would not get interferred with from macrovision defeaters that was also above line 17, so that was probably also on lines below macro. man, this is some blast from the past type stuff.
  - api 5y ago
    Today you can get HDMI copy protection strippers in the form of certain exact model numbers of HDMI signal splitters. You have to get the exact correct model and it will pretend to be a DRM-enabled HDMI endpoint and strip it on the split end. You do not have to plug two HDMI monitors in. Just one is fine. They will enable things like Amazon or Roku HDMI dongles to work with computer monitors that do not support HDMI encryption. The most common use is just that, not to pirate anything.
anthk 5y ago
I remember Nagravision on Canal+, a paid TV channel in Europe. Most people pirated it on TV cards because: - Nagravision on a Pentium 2 was trivial to decode - Soccer - Porn - Blockbusters
- wut42 5y ago
  There was a really good article about Canal's protection scheme and history lately on HN. I cannot find it sadly :( Edit: got it! [1] and previous discussion [2] [1]: https://fabiensanglard.net/discret11/ https://fabiensanglard.net/discret11/ [2]: https://news.ycombinator.com/item?id=23455033 https://news.ycombinator.com/item?id=23455033
imglorp 5y ago
Wow, that's the same MacroVision company, now Tivo, that bought Globetrotter for the FlexLM licensing tools. Talk about a vertical market, this one company has been irritating media and software customers alike for decades. https://en.wikipedia.org/wiki/TiVo_Corporation https://en.wikipedia.org/wiki/TiVo_Corporation
- linksnapzz 5y ago
  Deeply disappointed that Tivo is now associated with Macrovision && FlexLM, the software equivalent of a rusty razorwire chastity belt. I've spent way too much time in my career swearing at lmgrd....
  - imglorp 5y ago
    Yeah, back when you'd need to wire lmgrd into whatever product you were building and also administer it on your lan for whatever tools you bought. Static, floating, HA, so many things to confuse or go wrong. The whole DRM design pattern is a chain of weak links designed to keep a product from working. The customer is only satisfied if and only if nothing in the chain broke today, yet.

Steve44 5y ago

> which would mess with the vertical-blanking signal in a way that wasn't particularly noticeable on playback, but would mess with VHS recording On a related note, one of the copy protection systems I put on some Sinclair Spectrum cassette games involved changing the baud rate part way through loading. It was over 35 years ago so the details are hazy, but I had a custom "master maker" to play the audio[1] and at a specific byte count would change the frequency. The mastering and duplication machines coped with it fine and the loader was written to expect it, but it threw out most home tape to tape systems for reasons I can't exactly remember. [1] These were usually recorded directly from the Spectrum onto 2 inch reel to reel tapes in a studio, that was then used as the master at the duplicators.

dylan604 5y ago

Macrovision only worked on VCRs with the Automatic Gain Control (AGC) enabled. It was super easy to defeat by disabling the AGC, or if you had more sophisticated equipment like a time base corrector (TBC) or similar. These dubs will still have the Macrovision as is, but it won't affect the recording's video signal. Using a standards coverter NTSC->PAL for example would completely remove the macrovision from the dub.

LeoPanthera 5y ago
You could buy macrovision strippers from high street stores for years, Radio Shack / Tandy was a good candidate, they were usually sold as "video enhancers" or "video stabilizers" or similar language.
- dylan604 5y ago
  Right, those were the consumer names of time base correctors. Edit: https://en.wikipedia.org/wiki/Time_base_correction https://en.wikipedia.org/wiki/Time_base_correction
  - LeoPanthera 5y ago
    I don't think they were that advanced. The cheap consumer stuff would just use analogue circuitry to blank out the signal during the vertical blanking interval.
    - dylan604 5y ago
      It depends on the model. There were some that would allow one to adjust the contrast/chroma/etc. Of course it was all analog circuits, that's what made it all so accessible! Also, it probably wouldn't blank out the entire blanking as you'd lose CC or Teletext data. I forget the exact lines the macrovision appear on, but it was much higher than 17. We also used to embed ID codes in the blanking that would not get interferred with from macrovision defeaters that was also above line 17, so that was probably also on lines below macro. man, this is some blast from the past type stuff.
- api 5y ago
  Today you can get HDMI copy protection strippers in the form of certain exact model numbers of HDMI signal splitters. You have to get the exact correct model and it will pretend to be a DRM-enabled HDMI endpoint and strip it on the split end. You do not have to plug two HDMI monitors in. Just one is fine. They will enable things like Amazon or Roku HDMI dongles to work with computer monitors that do not support HDMI encryption. The most common use is just that, not to pirate anything.

anthk 5y ago

I remember Nagravision on Canal+, a paid TV channel in Europe. Most people pirated it on TV cards because: - Nagravision on a Pentium 2 was trivial to decode - Soccer - Porn - Blockbusters

wut42 5y ago
There was a really good article about Canal's protection scheme and history lately on HN. I cannot find it sadly :( Edit: got it! [1] and previous discussion [2] [1]: https://fabiensanglard.net/discret11/ https://fabiensanglard.net/discret11/ [2]: https://news.ycombinator.com/item?id=23455033 https://news.ycombinator.com/item?id=23455033

imglorp 5y ago

Wow, that's the same MacroVision company, now Tivo, that bought Globetrotter for the FlexLM licensing tools. Talk about a vertical market, this one company has been irritating media and software customers alike for decades. https://en.wikipedia.org/wiki/TiVo_Corporation https://en.wikipedia.org/wiki/TiVo_Corporation

linksnapzz 5y ago
Deeply disappointed that Tivo is now associated with Macrovision && FlexLM, the software equivalent of a rusty razorwire chastity belt. I've spent way too much time in my career swearing at lmgrd....
- imglorp 5y ago
  Yeah, back when you'd need to wire lmgrd into whatever product you were building and also administer it on your lan for whatever tools you bought. Static, floating, HA, so many things to confuse or go wrong. The whole DRM design pattern is a chain of weak links designed to keep a product from working. The customer is only satisfied if and only if nothing in the chain broke today, yet.