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Thousands and Thousands of Hours of PVR TV
Thomas Hawk writes "Cory Doctorow is posting over at Boing Boing about some technology that he apparently saw this weekend at London's Open Tech conference. According to Cory, this new technology from Promise TV takes the form of a home-built PVR with lots of high-capacity hard drives and claims to be able to record every show on every channel being recorded in the UK for an entire month. 'Why program a TiVo to get certain shows for you when you can record every single show on the air, all at once, and then use recommendations, search, a grid, or any other means you care to name to figure out which of those thousands and thousands and thousands of hours of programming you want to watch.' The company seems somewhat cryptic with a simple website that appears to be collecting your email addresses for an announcement in August. "
and there is still nothing to watch on TV!
Their next product: a home-built device that downloads the entire Internet for you to browse at your leisure...
well, with my PVR machine I record at 9Mbps for video and 384Kbps for audio, barely over 1MB/s. With two tuners, that's just over 2MB/s. Watching one of the previous recordings while recording two shows at the same time, that's just over 3MB/s. Even a mediocre HD can handle that no problem. Hell, while it's doing that it's also either scanning a show for commercial breaks or recompressing that 4GB/hour mpeg2 stream to a 1GB/hour mpeg4 stream, so there's a bit more workload, still doesn't break a sweat. So, one HD per recording is way overkill.
Let's make some calculations assuming that they're going to record all the DVB-T ("Freeview") content in the UK. I watch DVB-T in Spain using a MythTV box but the numbers should be roughly the same as for the UK.
45 mins recording of one channel = 1401390703 bytes
=> 1 hour = 1868520937 bytes
=> x 24 hours/day x 30.5 days/month = 1.37 TB per month per channel
Now there are about 30 freeview channels so we would need 41 TB of storage .... that's 82 500GB hard disks in RAID0! Which would occupy something like half a rack and use about 1kW of power ...
Even to record the 5 main channels would be nearly 7 TB - still a lot of noisy spinning hard disks to stick under the TV. This doesn't sound like a feasible idea with the size of today's hard disks.
As this sounds like pure marketing, we can make some assumptions:
a) Number of channels included will be the minimum available to all.
b) It'll be "VHS quality" recording.
There are 5 terrestial TV channels in UK:
BBC1
BBC2
ITV (commercial)
Channel 4 (commercial)
Channel 5 (commercial)
We've about 50 via digital TV, and loads more via cable or satellite.
However there are only 5 available right now.
So, that's 5 channels * 24hrs * 28 days = 3360 hours of recording.
Lets assume a VCD bitrate of 1300kbit/s video 128kbit/s. Total 1428kbit/s.
Number of seconds in 3360 hours
= (3360*60)*60
= 12,096,000
So, for all that video we'll need
= 1428 * 12,096,000
= 17,273,088,000 kbit
= 17,687,642,112,000 bits
= 2,210,955,264,000 bytes
= 2,159,136,000 kilobyte
= 2,108,531 megabytes
= 2,059 gigabytes
So that's like 4 * 500gb drives plus 1 * 120gb drive to correct for the drive maker's marketing departments.
I'm using VCD/MPEG as a basis for this, they'll invariably be using a better codec, probably with far stronger compression.
Insightful? Hah!
Capture cards? 30 feeds? Don't be so analogue and old school. It only needs to save the multiplexes. Which on terrestrial digital is about eight including all the radio stations.
Right assuming it's digital only, it needs as many 'frontends' as there are multiplexes. Modern day silicon (non can/discrete component) tuners are pretty cheap and rather small. You'll also need the demodulators to go with them. All of which would fit easily on a single PCI card. Then you just process each of the multiplexes' transport stream enough to remove the redundant data such as the NITs and record the rest on to the harddrives as a stream.
Something like a Sky box already does this with two transport streams. One is recorded for the 'trick mode' pause live TV etc and one for recording a program. It will also play back a third stream from the disc. A more powerful PC based machine could easily cope.
Dude, if I have my own T1 line and a cute girl 3 doors down, I'm not going to talk to her, I'm going to use my T1 to stream hidden webcams from her house and charge $29.95/month for membership to the site.
Talking to a cute girl := 1% chance of something that could be called success. := 100% chance of buying a russian bride.
Selling pics of a cute girl to pervs and collecting $$$
If I knew the wedgies I gave you back in 6th grade would have resulted in this . . . I might have taken a moments pause.
Only on /. would this get modded insightful.