Questions over the history of Macrovision
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Having not used many VHS tapes for a long time, I want to ask if anyone knows my questions about Macrovision protection (the main form of copy protection used for them).
First off, if you were to look in a home at 100 prerecorded tapes from a wide array of companies (from the 90s), how many out of that 100 would contain Macrovision technology? Guessing the majority, but not all. I still have one, and it does contain the encoding.
Wikipedia also claimed that the technology has been used on DVD recorders, along with cable/satellite boxes. I'm aware that DVD recorders tend to refuse to record Macrovision content, but I never knew any contained the encoding to prohibit copying other material. I've also never experienced issues in the past over copying off of Sky and various cable boxes. Do only a few channels use the code, or is this in America?
Finally, is the quality of Macrovision VHS video worse than unprotected VHS content. I have an old Bob the Builder tape from 15 years ago, and the picture is somewhat grainy. Is this the Macrovision, or just age?
Please answer these questions if you know any info.
First off, if you were to look in a home at 100 prerecorded tapes from a wide array of companies (from the 90s), how many out of that 100 would contain Macrovision technology? Guessing the majority, but not all. I still have one, and it does contain the encoding.
Wikipedia also claimed that the technology has been used on DVD recorders, along with cable/satellite boxes. I'm aware that DVD recorders tend to refuse to record Macrovision content, but I never knew any contained the encoding to prohibit copying other material. I've also never experienced issues in the past over copying off of Sky and various cable boxes. Do only a few channels use the code, or is this in America?
Finally, is the quality of Macrovision VHS video worse than unprotected VHS content. I have an old Bob the Builder tape from 15 years ago, and the picture is somewhat grainy. Is this the Macrovision, or just age?
Please answer these questions if you know any info.
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http://www.mediacollege.com/video/editing/macrovision/
It didn't really answer my questions, though. Is there a list, somewhere, of items that used the technology?
Basically DVD players and VCR's. Some far eastern DVD players could disable macrovision.
There have been a number of occasions where Sky boxes have started inadvertently adding MacroVision (cured by the usual unplugging), but also instances where a TV channel accidentally permanently set the flag ON.
'Usually' HD channels have the MacroVision flag set, and SD ones don't.
Google lists at least 10 pages on the subject including the site recommended to you.
And what are some non-HD Sky/Virgin channels which periodically use the Macrovision flag?
On HDMI that same flag can turn on HDCP which is the HDMI copy prevention system. With HDCP if the source detects it is connected to a recording device it simply turns off the HDMI output.
In theory any channel can set the copy prevention flag. There is no reason why it should only be HD or only pay channels for example.
Why all the questions about Macrovision, if you don't mind my asking?
Also with a DV capture device in infinitely superior quality.to a PC with a firewire interface, however I didn't realise the OP wanted to know how to defeat a copy protection system (no matter how poor the results are and how weak the system is). Is that allowed here ?
I can't really see the point, unless the content is not available on DVD.
I'm just interested in certain old technology, this being one type(I have no intention to break it).
As to the other point which has not been answered, no, it does not make it more grainy (that is caused by cheap tape stock which loses signal over time) but it does show as a pulsing of the black level in low light footage and also a more intrusive head switching point - it has a bright area recorded in the lower left of the image.
I have a JVC VCR (from the 1990's) which has 388 in the model number that has a switch on the front panel to cancel the Macrovision and allow VHS to VHS copy.
Not really true - MacroVison DOESN'T exist in the digital age (it can't, there's no where for it to be) - in your flawed example the MacroVision is obviously on the analogue VHS tape, and is detected by the analogue input to the recorder (just as it would be with a DVD recorder as well).
Macrovision disrupted the source sync signal just enough that a CRT TV could still ope with the instability but the AGC of a recording VCR would fluctuate and produce a recording where the brightness fluctuated too. For domestic machine to machine copying then that was game over. But in the Pro world we used Time Base Correctors and preblacked tapes to lay down a stable sync pulse track before copying. The source was also played through a TBC to stabilise the sync. VHS to VHS was still not great, but the results were tolerable at least.
The semi-pro world caught up to some degree when Panasonic release their frame store TBC technology.
Don't see why not?, just as the external boxes were perfectly legal - the MacroVision system didn't only stop copying, in a number of cases it also upset the TV you were trying to watch a tape on.