Shock Horror! TV Network Using Digital Technology

5 responses to “Shock Horror! TV Network Using Digital Technology”

1. 

   Tim Duggan

   November 19, 2009

   Tapes are still used to an extent in TV due to many reasons, primarily cost and speed. Also don’t confuse going tapeless for going digital; digital video tapes have been around for a long time now.

   The cost/capacity ratio is much better for a cassette/XDCAM disc compared to HDDs/Flash, HDDs don’t come in boxes of 100 for a three figure sum just yet. Tapes are much more robust than a HDD. The most sturdy media is a well sealed reel to reel tape – no moving parts whatsoever to damage in transit. Flash memory is getting there in price and may be the way forward, but even at the hundreds of GB size they can be too small in some situations. Tapes can be sent out and forgotten. I don’t think you could do that with HDDs yet.

   Tape formats are universal whereas there are many video file formats and codecs. Cross compatibility of broadcast systems (NOT editing systems) has only been dealt with recently as data transfer and automated transcoding infrastructure has become available. Something the radio media had less trouble with when they went tapeless.

   The kind of high speed broadband infrastructure needed to transfer broadcast video point to point quickly isn’t set up. The fibre optic links commonly used between stations (and other locations) are video based so material transfer has to be managed. That means two people communicating when to start recording and playing things. These links can be set up on an ad-hoc basis; companies with a fibre can link up with some place over 1 or 2 network links to another company they may only ever deal with once. It’s big benefit is it’s real time, news programs know something 1 minute long will take 1 minute to send, so they can be sent right up to deadline minus duration. The content is also visible while it’s transferred without any hassle. This technique is of course based on older analogue leased line/satellite layouts, the links have remained only they are now digital (and MPEG normally). Also the staff procedures for these links/transfers are universal in TV so they have remained and saved on retraining.

   Program/Commercial production companies can be any size (how many people edit at home now?) and don’t normally bother installing that kind of equipment; their vision is sourced from camera compatible media (Tape, XD Cam cartridge, HDD or Flash) more often than not in their office. A company could have more than one office and could set up a high bandwidth network between them if they wanted remote ingest. But it would be pretty rare that they can’t wait for a file to transfer over a slower/cheaper link.

   Another point is the bandwidth for these links is still rather expensive; these aren’t IP packet links, they must be able to sustain a constant base rate the whole time. To be cost effective, media companies would have to buy up wholesale bandwidth like and ISP or hosting company. Plus they would have to hope the client has done the same thing or a file transfer could take a while. Companies send items to so many locations on an ad-hoc basis that it’s just too hard to keep track of who has how much bandwidth and how long it takes to send them something. Recent media reports show that it’s quicker to send something by pigeon than a 1:1 data transfer. I know they concern the retail market but the issue does concern larger users too.

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2. 

   David Francis

   November 20, 2009

   “Recent media reports show that it’s quicker to send something by pigeon than a 1:1 data transfer.”

   I think it’s important that this statement doesn’t get taken out of context, so be sure to read a report of what happened: http://news.bbc.co.uk/2/hi/8248056.stm .

   Certainly, if decent infrastructure is in place to deal with such issues as outlined in the comment above, then the advantages are quite numerous.

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3. 

   Stephen Gentle

   November 20, 2009

   Your image with the article is a very misleading, to say the least… All the tape that is generally used is digital already, and very high quality (unlike VHS). DigiBeta (the successor to Betacam SP), for instance, is still used a lot for SD content, and then there’s HDCAM, HDCAM SR and D5. Even though the tapes are reasonably cheap (a HDCAM SR tape goes for around $120 for a 64 minute tape – sounds expensive but it’s not really when you take into account that the data stream is 600 MBit/s), the decks are not – decks typically go for $40,000 to $90,000 – eg. http://www.abelcine.com/store/product.php?productid=1000208&cat=343&page=1

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   1. 

      b8two

      November 21, 2009

      64 minute TAPE = 3840 seconds Times 600MBit/s = 2304Mbit a TAPE devide bits in to bytes (/8) 288Mb for 64 minutes.

      $120 / 2.304 = $52.08 $ per Gbit
      $120 / 0.288 = $416.67 $ per GB

      Sorry, still sounds expensive

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4. 

   Michael White

   November 22, 2009

   A full length movie at original (uncompressed) resolution is too big to transmit – you are looking at multiple terabytes. Based on (possibly faulty) calculations, an uncompressed HDTV show requires around 100 GB/hr. Since video compression is lossy, this needs to be the final step of the process

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