VHS: A Free format..?

[Gogeden]

I was watching a movie and I had a thought pop in my head. Would VHS qualify as a free (As in freedom) format? It doesn't have any DRM (That I could think of). What do you all think? Granted, it's a dated technology.

[mr john]

There were things on some VHS tapes to make them read only. This prevented you from taping things on them. This could be bypassed with some cellotape or masking tape.

Also, it may have been possible to copy the videos, but many of them contained FBI warnings and copyright messages etc.

Just because it was possible to copy them didn't mean that it was legal to They were only as free as the laws that governed them.

[Gogeden]

Are there any Free physical formats out there?

[SJR Dorset]

There are ways of copy protecting VHS recordings which could count as DRM.

[Gogeden]

There are ways of copy protecting VHS recordings which could count as DRM.

Yes, but all you would have to do is cover that square on the face of the tape. I don't know of... OH! wait, region DRM effects VHS players. Crap.

Although... when I compare VHS to DVD and Blu-Ray, it is MUCH more free than those two. Hmm...

[mips]

VHS is a open standard but not a free format the way I interpret it. JVC collected billions in royalties for the use of VHS by other companies.

As for DRM yes it could be DRM free but most commercial tapes had some form of DRM or the other, Macrovision being the most common in order to prevent people from making 'backups'.

Then you also had unintended 'DRM' (or maybe it was intentional) with different local standards like NTSC,PAL,SECAM and even within those standards there were differences between countries where the sound carrier for example was on a different frequency.

[lisati]

After trying to make digital backups of some of my aging video library, I can confirm that there are ways of protecting VHS tapes against copying. The write-protect tab has nothing to do with it: all that does is help prevent accidentally recording something over the top of what's already there, and is easily bypassed with some tape over the hole.

[SJR Dorset]

Yes, but all you would have to do is cover that square on the face of the tape. I don't know of... OH! wait, region DRM effects VHS players. Crap.

Although... when I compare VHS to DVD and Blu-Ray, it is MUCH more free than those two. Hmm...

The square on the face of the tape is stop you accidentally overwriting the tape, not a form of copy protection.

VHS copy protection systems mess about with the timebase so that any copies are unplayable.

[Gogeden]

The square on the face of the tape is stop you accidentally overwriting the tape, not a form of copy protection.

VHS copy protection systems mess about with the timebase so that any copies are unplayable.


Thanks for elaborating the square! :)

How does the timebase scramble work?

Also, what if I were to record a video on DVD on to VHS?

[davetv]

The way a VHS tape makes itself uncopyable is one of the earliest forms of DRM (sorta).

The tape introduces random digital noise to the video output during the "vertical flyback interval". This is where the electron beam in your CRT TV goes from the bottom left to the top right for a retrace of the interlaced or next primary frame.

You can buy a electronics solder together kit that can correct the 192 microsecond vertical flyback period in the video output.

Your tv relies on the "leading edge" ...ie: it's start, and initiates it's own 192 us period. A video recorder on the other hand cannot maintain vertical synchronization. It tries to record everything. So you cannot copy without above mentioned kit.

The kit uses the "leading edge" and generates it's own "1" for that time that overrides the digital garbage during the interval. I have one, bought it at Jaycar Australia, difficulty 5/5 ... some surface mount high bandwidth op amp chips. Works a charm. REALLY NEEDS some expert soldering with a nice iron (mines a Weller WTCTP) and a fine tip!!

BTW .. a DVD will be uncopyable via a later technique ... The brightness keeps going from black to overbright ... then sync issue... rinse and repeat. A different exploit of a VHS recorder. Modulate the DC level of the signal.

I am old ... and used to fix tv's - using PAL-D 625 for above timings

[bouncingwilf]

Maybe I'm being naive, but I you can buy a VHS -> USB cable that just redirects the output of a VHS player to PC where any number of software packages will capture the data. Whether it's legal to do this depends very much on the conditions under which the VHS tape was created/acquired.

Bouncingwilf

[Bachstelze]

VHS is not a format, it's a medium.

[davetv]

I would say magnetic tape is the medium, VHS is the format ... as opposed to BETAMAX ... same medium, different format.

[Bachstelze]

I would say magnetic tape is the medium, VHS is the format ... as opposed to BETAMAX ... same medium, different format.

By that logic, CD-ROM and Blu-ray are the same medium: plastic.

[Jakin]

D-VHS probably has DRM implementations. (I wanted one for the longest time... but DVR prices fell much faster- so..)

[davetv]

I agree Bachstelze, plastic with a reflective layer encompassed within, containing "depressions" and "lands" that can be read as a varying signal by a laser.

(by shining a laser upon it and reading the signal and accomplishing tracking using photo-diodes)

[bootedguy]

Radio Shack use to sell a filter which would take care of the macrovision copy protection. Also, I believe hauppauge cards will work as well.