The premium channel HBO announced that it will introduce HD versions of all 26 of its channels in MPEG-4 format. HBO said that it had no choice because of the bandwidth savings of MPEG-4 over MPEG-2. This transition will start in the fourth quarter of 2007 and complete in the first quarter of 2008. HBO will transmit the HD channels using 8 Mbps of bandwidth for each.
This is good news for the TelcoTV providers virtually all of whom will used MPEG-4 as their native format for HD programming. They can take these MPEG-4 feeds and use them directly.
It is not as simple for the cable companies. They will have to transcode these MPEG-4 feeds to MPEG-2. This involves extra expense for the transcoders and potentially some loss of quality.
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3 comments:
Hi Bob
is this a theoretical number or is it really possible with today's encoders? does it mean that service providers can offer HD channels that take only 8Mbps each? if so, who the heck needs 100Mbps per subscriber? with 3 HD streams and another 10-15Mbps for everything else, even 50Mbps looks like too much
Thanks,
Ohad
Ohad,
8 Mbps is a mainstream estimate for the bandwidth required for HD channels. I have been told that demanding sports content with lots of camera pans can be accomodated at this speed. Harmonic says that it can support most HD content at 6 Mbps and that 3 Mbps is enough for a lot of programming.
In any case, 8 Mbps is a widely accepted value for the bandwidth required to support HD channels.
The amount of bandwidth required depends on the numbers and type of video streams and the speed of the Internet service. ATT is planning on a minimum of 25 Mbps with a maximum of 6 Mbps for the Internet data service. This is more than enough for one HD stream and 3 SD streams. Countries with fewer TVs in each home can get along with less bandwidth. The 15 Mbps available from ADSL-2+ will be adequate.
On the other hand, do not underestimate the speed at which HD will be adopted. In the U.S. you can get a smaller (19" to 26") HD set for about $400 and prices are still dropping rapidly.
Once you get used to watching HD programming you do not want to go back. We have seen this ourselves since our HD set has been in the shop. People will migrate from one HD set in the home to all HD sets in the home, at least here in the U.S. This will significantly increase the bandwidth demand for these services.
You also have to factor in DVR recording. If you watch one live program and record anoter simultaneously, this requires two simultaneous streams. The ATT set-top box permits recording up to four simultaneous programs, each of which must be streamed.
I think that 25 Mbps will not be enough bandwidth quite rapidly here in the U.S. 50 Mbps looks like enough for a while.
Keep in mind that Internet data service speeds will increase at the same time. If the U.S. cable companies really deploy DOCSIS 3.0 rapidly to offer 100 Mbps cable modem services, ATT and Verizon will have to respond. Verizon is in good shape with its fiber network but ATT will be in a tough position with VDSL.
Finally, do not underestimate the ability to utilize bandwidth. I remember when 300 bps was a breakthrough. I would have thought then that the 3 Mbps DSL line I have today to be science fiction. Today, I am chafing to get 20 to 30 Mbps.
Ohad, I think you are young enough that you will someday have a 1 gigabit service and feel constrained by its "limited bandwidth"
Thanks for the answer, Bob. I really appreciate it.
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