[Robert_Gourley]

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.

[grahamlthompson]

Quote:

Originally Posted by Robert_Gourley

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.

http://www.mediacollege.com/video/editing/macrovision/

[Robert_Gourley]

Quote:

Originally Posted by grahamlthompson

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?

[grahamlthompson]

Quote:

Originally Posted by Robert_Gourley

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.

[Nigel Goodwin]

Basically MacroVision was a tape system - DVD players (and Sky boxes etc.) added it to their output in response to a flag on the disc or programme. Macrovision itself wasn't carried on DVD or Digital Satellite as it's not possible on a digital system (so was added to the analogue output by the receiver/player).

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.

[anthony david]

On Digital boxes had it, it was turned on by data in the bitstream. When On Digital ceased my Philips DTX 6371 box turned it on at random on the channel used for BBC 4 ruining VHS recordings. It only happened on BBC 4. The signal was inserted in frame blanking on many commercial VHS tapes. It didn't normally affect picture quality part from a slight disturbance at the very top of frame on some TVs.

Google lists at least 10 pages on the subject including the site recommended to you.

[Robert_Gourley]

I don't have Sky at my house, but have tested the HD feeds on Freeview (truncated to SD SCART) and have never had any Macrovision trouble. I've never had any trouble when testing the Sky HD box at my grandparents house, either (although they get only the free HD channels). Is it only HDMI connectors that trigger the interference, or only the pay HD channels?

And what are some non-HD Sky/Virgin channels which periodically use the Macrovision flag?

[chrisjr]

Quote:

Originally Posted by Robert_Gourley

I don't have Sky at my house, but have tested the HD feeds on Freeview (truncated to SD SCART) and have never had any Macrovision trouble. I've never had any trouble when testing the Sky HD box at my grandparents house, either (although they get only the free HD channels). Is it only HDMI connectors that trigger the interference, or only the pay HD channels?

And what are some non-HD Sky/Virgin channels which periodically use the Macrovision flag?

Macrovision will only affect the SCART output as it is a strictly analogue system. The actual raw digital signal from which the analogue output is derived won't have Macrovision. But in the signalling data that accompanies the video and audio will be a flag that turns on a Macrovision circuit on the SCART feed.

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.

[Winston_1]

Signals with macrovision content can be recorded with JVC/Ferguson piano key VHS machines, some Philips VHS machines and Betamax machines. The recordings still contain macrovision but the above machines record it OK.

[Robert_Gourley]

Any channel can use it, yes, but I meant more if there are any which do use it? Guessing some of the film channels, but don't know for sure.

[Chris Frost]

Quote:

Originally Posted by chrisjr

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.

Indeed. It may be a specific requirement for broadcasting certain feature films for example.

[Chris Frost]

Quote:

Originally Posted by Robert_Gourley

Any channel can use it, yes, but I meant more if there are any which do use it? Guessing some of the film channels, but don't know for sure.

Why all the questions about Macrovision, if you don't mind my asking?

[grahamlthompson]

Quote:

Originally Posted by Winston_1

Signals with macrovision content can be recorded with JVC/Ferguson piano key VHS machines, some Philips VHS machines and Betamax machines. The recordings still contain macrovision but the above machines record it OK.

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.

[Robert_Gourley]

Quote:

Originally Posted by Chris Frost

Why all the questions about Macrovision, if you don't mind my asking?

I'm just interested in certain old technology, this being one type(I have no intention to break it).

[mooghead]

Macrovision was brilliant for what it was invented for.. there is no modern digital equivalent... people just shamelessly thieve now.....

[Robert_Gourley]

Agreed - back in the day of VHS most people did not have the technology to remove the encoding and (make a good) copy the video on the tape. Now someone can just use a variety of DVD streaming software that completely ignores the vertical blanking, therefore removing the Macrovision on that copy.

[Soundbox]

Macrovision still persists in the digital realm. For instance play an encoded VHS into a Digital 8 camcorder (which turns the analogue stream to digital) and the camcorder says 'copyright material'.

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.

[Nigel Goodwin]

Quote:

Originally Posted by Soundbox

Macrovision still persists in the digital realm. For instance play an encoded VHS into a Digital 8 camcorder (which turns the analogue stream to digital) and the camcorder says 'copyright material'.

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).

[Chris Frost]

Quote:

Originally Posted by Robert_Gourley

...and (make a good) copy the video on the tape.

A good copy from VHS?...... Now there's an oxymoron, if ever I heard one.

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.

[anthony david]

I have just found a so called video signal conditioner (SB-3670) bought from Maplin years ago, it replaced frame syncs together with several lines either side to remove head switching. It made it possible to copy protected tapes but introduced a bit of sit-up at the same time. At work we either dubbed VHS-VHS via a Snell and Wilcox TBC or dubbed the tapes to Beta SP first. Oddly sometime the dub looked better than the original, we assumed that although the picture quality deteriorated, the removal of jitter and the creation of new syncs by the TBC made the picture look superficially sharper.

[Winston_1]

Quote:

Originally Posted by Soundbox

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.

Really, I'm surprised that was allowed.

[Nigel Goodwin]

Quote:

Originally Posted by Winston_1

Really, I'm surprised that was allowed.

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.