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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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10th Jul 2019, 10:38 pm | #1 |
Octode
Join Date: Jun 2018
Location: Essex, UK.
Posts: 1,307
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Video On Compact Cassette
Hi,
I've been thinking about if video (Albeit very poor quality) could be captured, and replayed on a compact cassette, using a normal cassette deck (and PC software) I've seen those cameras which record onto compact cassette in black and white, which sparked the idea. I was playing around with the idea and put the video plug of a composite lead into the right channel input of a cassette player and mono audio into the left. I pressed record on the cassette deck, and both VU meters jumped to life. Left bounced, whereas right stayed relatively still on around 20-40% I recorded the cassettes data directly to Audacity, and there were two wave forms. I sent the file to a friend who has composite in on their TV and played the audio. The audio played fine, and there was a blue band at the top of their screen. What would need to be done to get a full video (Monochrome or colour is fine) I think the frequency would need to be increased, but I'm not too sure. I did try increasing the frequency in audacity, but every time I tried, audacity crashed. This is only a small project/thought so it doesn't matter if it's do-able or not, although I have seen it done before, in devices made for that purpose. What are your thoughts on this? Thanks |
10th Jul 2019, 10:44 pm | #2 |
Hexode
Join Date: Nov 2010
Location: Sheffield, South Yorkshire, UK.
Posts: 278
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Re: Video On Compact Cassette
Hasn’t techmoan on you tube and the 8 bit guy done something on this?
Regards, Alan. https://m.youtube.com/watch?v=TCXJ5twf5tM |
10th Jul 2019, 10:50 pm | #3 |
Hexode
Join Date: Dec 2011
Location: Wigan, Greater Manchester, UK.
Posts: 291
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Re: Video On Compact Cassette
The sound would be fine. Unfortunately the bandwidth of the video would only be around 10kHz. The line sync pulses are of the order of 15kHz, so the cassette tape would not record that, so you woul not see anything.
The 8 bit guy takes about using an ordinary cassette tape in a video camera. The camera would use helical scan, which would give a tape to head speed around 100x that of an audio tape player This would than allow a vieo signal to be recorded. |
10th Jul 2019, 10:51 pm | #4 |
Octode
Join Date: Jun 2018
Location: Essex, UK.
Posts: 1,307
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Re: Video On Compact Cassette
It was actually the 8 bit Guy's video that made me think of the idea but it used technology designed to do this. I haven't seen any done by Techmoan - he did do one with videos on 45s if that's what you're thinking of?
Thanks |
10th Jul 2019, 10:58 pm | #5 |
Nonode
Join Date: Oct 2008
Location: Warsaw, Poland and Cambridge, UK
Posts: 2,681
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Re: Video On Compact Cassette
There was a Fisher-Price toy camcorder which used an audio cassette to record video. I think it ran the tape fast and used a simple digital compression scheme (throwing away most of the image!) to get its crude results.
An unmodified audio cassette recorder, even the very best with frequency response up to 20kHz on a good day, won't even record the sync pulses usefully, never mind any picture content. Chris
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10th Jul 2019, 10:59 pm | #6 |
Hexode
Join Date: Dec 2011
Location: Wigan, Greater Manchester, UK.
Posts: 291
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Re: Video On Compact Cassette
As a post script, way back in 1970 I had a video recorder that used linear scan. It had 7 inch spools of tape and would go so fast that the tape would last for around 4 minutes. Even then on 405 lines the picture was poor. The sound was good though!
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10th Jul 2019, 11:34 pm | #7 |
Nonode
Join Date: Jun 2013
Location: Surbiton, SW London, UK.
Posts: 2,801
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Re: Video On Compact Cassette
If you could convert the composite video to Baird 32-line standard electronically this
would fit on an audio track. |
11th Jul 2019, 1:04 am | #8 |
Octode
Join Date: Jun 2018
Location: Essex, UK.
Posts: 1,307
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Re: Video On Compact Cassette
Thanks for the replies.
I did take tape speed into account, and expected very poor quality image results, if any but was expecting them more than not. I did try find out online freqeuncies of each factor, ie. the frequency when something will show on screen and tried to match this on Audacity - with no luck. How could i convert it to Bairds 32 line standard? And how would i get a display from it? (Or would i need a converter from the 32 Lines to 625 for a standard CTV?) Thanks |
11th Jul 2019, 7:10 am | #9 |
Rest in Peace
Join Date: Jul 2011
Location: Bridgnorth, Shropshire, UK.
Posts: 787
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Re: Video On Compact Cassette
Some people in the Narrow Bandwidth Television Association have done exactly as you describe: 625 -> 32 -> tape -> 32 -> 625. It is not easy, in particular, the large low frequency phase shifts of cassette recorders corrupts the waveforms making sync separation difficult.
It is only £5 to join the NBTVA cyber membership. You'd be made welcome and you never know - you might have some new ideas to bring to bear on the subject |
11th Jul 2019, 7:53 am | #10 |
Dekatron
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,088
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Re: Video On Compact Cassette
I was also thinking small line count, low bandwidth video. If Baird could make videodiscs in the 1920's (and there is even an off-air recording of BBC TV from the 1930's which somebody made using a home disc recorder) then it should be fairly trivial to use a cassette recorder in the 2010's.
I'd go out and buy an Aurora converter - quicker and cheaper than building a camera and display for 30-line! |
11th Jul 2019, 8:44 am | #11 |
Tetrode
Join Date: Oct 2006
Location: Severn Valley,Worcestershire, West Midlands, UK.
Posts: 56
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Re: Video On Compact Cassette
Slow-scan tv would also work.
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11th Jul 2019, 9:17 am | #12 |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
Posts: 2,534
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Re: Video On Compact Cassette
Karen O (above) is being as modest as ever. She has achieved this feat herself some years ago at an NBTVA Convention and I recall seeing a very convincing demonstration.
Steve |
11th Jul 2019, 12:09 pm | #13 |
Rest in Peace
Join Date: Jul 2011
Location: Bridgnorth, Shropshire, UK.
Posts: 787
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Re: Video On Compact Cassette
Let us not forget absent friends who achieved such feats long before I arrived on the scene, Steve.
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11th Jul 2019, 12:20 pm | #14 |
Octode
Join Date: Jun 2018
Location: Essex, UK.
Posts: 1,307
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Re: Video On Compact Cassette
Thanks for the replies
I've had a look on the NBTV website, and will seriously consider it. I would be quite interested in getting it working. I think Audacity has a syncing system, which might help. How much are the aurora converters? (I would also like to get into 405 Televisions too) I've never heard of slow-scan TV before, but I've just googled it. Is it a software and phone application, or are there special TVs for this? It'd be interesting to see Karens work, and how she did it, if possible, too. Thank you for the replies! |
11th Jul 2019, 1:13 pm | #15 |
Dekatron
Join Date: Feb 2005
Location: West Cumbria (CA13), UK
Posts: 6,130
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Re: Video On Compact Cassette
Even though these were 30-line recordings, I don't think JLB was able to extract a viewable image from them. It was only with a fair degree of computer processing that these images were subsequently recovered in the 21st century.
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11th Jul 2019, 1:30 pm | #16 | |
Nonode
Join Date: Sep 2017
Location: Stockport, Cheshire, UK.
Posts: 2,004
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Re: Video On Compact Cassette
Quote:
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11th Jul 2019, 2:37 pm | #17 |
Heptode
Join Date: May 2006
Location: Accrington, Lancashire, UK.
Posts: 978
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Re: Video On Compact Cassette
Years ago there was a toy, Fisher Price, and it said it recorded video on an audio cassette. I got one in for repair but it's a blur now. Not the picture but my memory. Surely we must appreciate helical scan was the only way. Although Ampex and a few others tried normal methods. In fact in the 60's Philips brought a mono tv out with two reels in the top that would record video. But video longitudally (sorry re spelling) come on!
We suffered with VHS and Beta, and for what they were, were ok. I remember a guy in the 70's, he claimed to mod a reel to reel tape deck for video. A sight nowadays. (dementia setting in) |
11th Jul 2019, 4:46 pm | #18 |
Rest in Peace
Join Date: Jul 2011
Location: Bridgnorth, Shropshire, UK.
Posts: 787
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Re: Video On Compact Cassette
The Pixelvision 3000(?) stored 90 line monochrome images at 15 frames per second onto chrome cassettes running 9 times normal speed. It included a standard converter/time base corrector for playback to a separate 525 monitor. It became something of a cult among amateur movie makers due to its ghostly blurry images.
The longitudinal VCR was the Telcan and ran tape at 200 inches/sec. The head gap was created using mosaic from video camera tubes. It worked but wasn't practical. |
11th Jul 2019, 4:57 pm | #19 | |
Nonode
Join Date: Feb 2005
Location: Worcestershire, UK.
Posts: 2,534
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Re: Video On Compact Cassette
Quote:
Steve |
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11th Jul 2019, 4:59 pm | #20 |
Administrator
Join Date: Dec 2002
Location: Cardiff
Posts: 9,073
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Re: Video On Compact Cassette
More info: https://en.wikipedia.org/wiki/PXL-2000
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