ProDigit
31st October 2018, 02:57
Last year, the 8-bit guy introduced me to the PX2000 via his youtube channel. Video here:
https://www.youtube.com/watch?v=TCXJ5twf5tM
It's a fisher price PXL-2000 camcorder that uses audio cassettes to record video on, built in 1987.
The device itself could record about 11 minutes of video, on a 90 minute cassette (5.5 minutes per side), at a resolution of roughly 10kpix, or 120x90 pix. The device ran the audio cassette tape at 9x the speed, to have sufficient bandwidth to record the pretty much 'raw' audio and video data.
The device was a total failure, due to the required bandwidth to record video footage on, The low resolution, the high tape drive recording speed, and the extremely bad lighting (high f-ratio of the lens, and low quality CCD sensor).
But times have changed, and so do our video encoders, our CCD chips, and our mobile CPUs.
Recording video footage on a cassette is by no means a replacement for current technology, but it's interesting from a point of view that 'it can be done'.
I've done some digging in the interweb, but found a lot of conflicting data concerning the speed and data that could be retained on a tape.
So from a point of view of comparing to older technologies, I can't state much.
Modern technology has improved since the 80's, and it's possible to have much more data on a tape, than was prior possible.
Cassette tapes basically work like old dial up modems; while it's still possible to get DSL speeds out of a tape, through more optimal use of frequency bandwidth.
There's not a lot of study done on what bandwidth is achievable from a tape, but I think I can estimate (open for any correction here, I'm only guessing)
When comparing tapes to audio CDs,
Audio CDs run at 16 bit, with a 20-20kHz resolution,
Audio tapes run at ~10 bit, with a ~25-18kHz, but more likely the cheaper tapes have a frequency response of ~30-16kHz.
The data of an Audio CD, roughly is 10MB/minute of audio (roughly 700MB of space for 70 min of music).
Based on the lower bitrate and audio frequency of cassette tapes, they should get about ~350MB per 70 min (175MB/side).
Tape drives aren't as precise as CD drives. They suffer of WOW and flutter, which could potentially corrupt data, thus the above number would be lower than that.
I've read somewhere on the webs (lost source), that a regular 60 minute cassette could hold up to 275MB of data, which is very close to the 300MB I would have calculated (350MB / 70min = 300MB / 60min).
I think a lot of people here could say how much video footage could fit in 275MB, 137MB per side;
If I had to guess, I've seen 480p streaming videos, stream as low as 65MB of file size per 20min of video footage using Opus as sound codec, and H.265 as video codec.
In that case, each side could host about 40 minutes of video footage, on a 60 minute audio cassette tape.
So, it might be possible to actually record 480p video footage, with current encoders, on a regular audio cassette, at single speed!
At the minimum, a device like this needs a 410k pix camera (about 41x larger), and at best, using quarter pixel motion, this device will need a 1708x960 pixel CCD (or 1.6Mpix), for optimal recording.
I wished there were some companies (esp. looking at China now, as this probably will not be a product that will attract many), that would invest a little R&D, pair a small CCD sensor, and recreate this ancient technology.
Just to see how far we've come.
And record video footage of reasonable quality, on an audio tape!
While the sales of audio tapes are on decline,
Playing video footage from an LP has been done, through Video LP.
Now where's the audio tape version?
Just thought of spitting the idea out here!
:thanks:
https://www.youtube.com/watch?v=TCXJ5twf5tM
It's a fisher price PXL-2000 camcorder that uses audio cassettes to record video on, built in 1987.
The device itself could record about 11 minutes of video, on a 90 minute cassette (5.5 minutes per side), at a resolution of roughly 10kpix, or 120x90 pix. The device ran the audio cassette tape at 9x the speed, to have sufficient bandwidth to record the pretty much 'raw' audio and video data.
The device was a total failure, due to the required bandwidth to record video footage on, The low resolution, the high tape drive recording speed, and the extremely bad lighting (high f-ratio of the lens, and low quality CCD sensor).
But times have changed, and so do our video encoders, our CCD chips, and our mobile CPUs.
Recording video footage on a cassette is by no means a replacement for current technology, but it's interesting from a point of view that 'it can be done'.
I've done some digging in the interweb, but found a lot of conflicting data concerning the speed and data that could be retained on a tape.
So from a point of view of comparing to older technologies, I can't state much.
Modern technology has improved since the 80's, and it's possible to have much more data on a tape, than was prior possible.
Cassette tapes basically work like old dial up modems; while it's still possible to get DSL speeds out of a tape, through more optimal use of frequency bandwidth.
There's not a lot of study done on what bandwidth is achievable from a tape, but I think I can estimate (open for any correction here, I'm only guessing)
When comparing tapes to audio CDs,
Audio CDs run at 16 bit, with a 20-20kHz resolution,
Audio tapes run at ~10 bit, with a ~25-18kHz, but more likely the cheaper tapes have a frequency response of ~30-16kHz.
The data of an Audio CD, roughly is 10MB/minute of audio (roughly 700MB of space for 70 min of music).
Based on the lower bitrate and audio frequency of cassette tapes, they should get about ~350MB per 70 min (175MB/side).
Tape drives aren't as precise as CD drives. They suffer of WOW and flutter, which could potentially corrupt data, thus the above number would be lower than that.
I've read somewhere on the webs (lost source), that a regular 60 minute cassette could hold up to 275MB of data, which is very close to the 300MB I would have calculated (350MB / 70min = 300MB / 60min).
I think a lot of people here could say how much video footage could fit in 275MB, 137MB per side;
If I had to guess, I've seen 480p streaming videos, stream as low as 65MB of file size per 20min of video footage using Opus as sound codec, and H.265 as video codec.
In that case, each side could host about 40 minutes of video footage, on a 60 minute audio cassette tape.
So, it might be possible to actually record 480p video footage, with current encoders, on a regular audio cassette, at single speed!
At the minimum, a device like this needs a 410k pix camera (about 41x larger), and at best, using quarter pixel motion, this device will need a 1708x960 pixel CCD (or 1.6Mpix), for optimal recording.
I wished there were some companies (esp. looking at China now, as this probably will not be a product that will attract many), that would invest a little R&D, pair a small CCD sensor, and recreate this ancient technology.
Just to see how far we've come.
And record video footage of reasonable quality, on an audio tape!
While the sales of audio tapes are on decline,
Playing video footage from an LP has been done, through Video LP.
Now where's the audio tape version?
Just thought of spitting the idea out here!
:thanks: