CRC is a one-way hash, not compression. Or, if you like, it's 100% lossy compression... On Thu, Aug 7, 2008 at 11:56 AM, John Willkie <johnwillkie@xxxxxxxxxxxxx>wrote: > Yeah, I can't wait to see that feature deployed in the wild, aside from > Thales PSIP/PSI generators region 1 rating region table, I've yet to see > that. (Of course, there was that bug that existed for about 6 years in one > of the stated decode tables …) > > > > I was thinking about how a CRC-32 can be considered as a compressed value, > too… > > > > That said, I should point out that one might be able to get 2:1 or 3:1 > compression with Huffman encoding in PSIP text strings, but nothing like > 50:1. > > > > John Willkie > > > ------------------------------ > > *De:* opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] *En > nombre de *Adam Goldberg > *Enviado el:* Thursday, August 07, 2008 8:44 AM > > *Para:* opendtv@xxxxxxxxxxxxx > *Asunto:* [opendtv] Re: From Broadcast Engineering - WRAL tests mobile DTV > > > > To be super ultra hyper technical, there is some (optional) compression of > text strings in PSIP. > > On Thu, Aug 7, 2008 at 11:41 AM, John Willkie <johnwillkie@xxxxxxxxxxxxx> > wrote: > > Well, to be hyper-technical, there is no compression of PSIP or PSI. They > are not sending uncompressed essence ... > > John Willkie > > -----Mensaje original----- > De: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] En > nombre de maitken@xxxxxxxxxx > Enviado el: Thursday, August 07, 2008 3:37 AM > Para: opendtv@xxxxxxxxxxxxx > Asunto: [opendtv] Re: From Broadcast Engineering - WRAL tests mobile DTV > > Not sure what your definition of 'full-bandwidth' is, but I can assure all > that they are not sending 'uncompressed' anything... > > Mark > Sent from my Verizon Wireless BlackBerry > > -----Original Message----- > From: "Don Moore" <don@xxxxxxxxxxxxxx> > > Date: Thu, 7 Aug 2008 02:40:56 > To: <opendtv@xxxxxxxxxxxxx> > Subject: [opendtv] Re: From Broadcast Engineering - WRAL tests mobile DTV > > > WRAL has the advantage of Full-Bandwidth to Cable and (I assume) > Satellite. The Raleigh Market has high cable/satellite penetration, > meaning that WRAL can sacrifice their OTA Bandwidth to mobile > customers since a large percentage of their viewers are cable and > satellite. The net result is different streams to different > receivers. > > They have the luxury of being able to feed cable homes one > uncompressed signal with its various sub-channels, while OTA viewers > watch the compressed ATSC signal. > > I'm not saying it's bad, it's just circumventing what the intention of > HDTV was supposed to be and doing something that most broadcasters can > not duplicate because of either their relationship with their local > cable systems or lack of advanced research in the technology. Not > everybody can pull this off. > > Are we creating One Program Service for Cable/Satellite/Internet and a > second for OTA? > > > > On Wed, Aug 6, 2008 at 11:41 PM, Tom Barry <trbarry@xxxxxxxxxxx> wrote: > > Supposedly from Broadcast Engineering though I copied it from AVS > > <http://www.avsforum.com/avs-vb/showthread.php?t=1056025>. I'm not sure > I > > understand it correctly but it looks like they got a total of 900 kbps > (2 > > channels, 300+600) after error correction overhead from using a total of > 4.5 > > mbps of the channel bandwidth. > > > > - Tom > > > > --------------------------------------------------- > > From Broadcast Engineering - WRAL tests mobile DTV > > Broadcast Engineering Mobile TV Update > > > > WRAL tests mobile DTV > > > > Users in Raleigh-Durham reported reliable signal reception in most parts > of > > the station's existing coverage area. > > > > WRAL-DT, the CBS affiliate in Raleigh-Durham, NC, owned by Capitol > > Broadcasting Company (CBC), conducted a series of mobile DTV tests last > week > > using the Mobile-Pedestrian-Handheld (MPH) system promoted by Harris > > Broadcast and others. Hosted by CBC's New Media Group, the tests featured > > seven handsets given to station executives living in different parts of > the > > state. Users reported reliable signal reception in most parts of the > > station's existing coverage area. > > > > To kick off the July 21-25 trial, the station hosted a reception last > > Tuesday in which about 50 participants were driven in a bus around the > area > > with prototype LG Electronics mobile handsets that featured > MPH-compatible > > reception chips inside. Signal reception of two channels (half rate at > > 600kb/s and one-quarter rate at 300kb/s) using about 4.5Mb/s (including > > turbo coding) of the station's 19.4Mb/s on-air DTV stream was reportedly > > strong everywhere they went during the 10-minute ride — even at 70 miles > per > > hour. > > > > The goal of the service, according to John Harris, WRAL's director of > > programming, is to extend the reach of the station's television channel, > and > > make it available everywhere our viewers are. The initial plan is to > > simulcast the on-air DTV signal. WRAL-TV broadcasts CBS network and its > own > > local programming in the 1080i HDTV format as well as in SD digital. > > > > "We're excited about the possibilities," John Harris, WRAL's director of > > programming, told Broadcast Engineering. "The priority is to offer WRAL's > TV > > signal in another way, in another place. I took one [handset] east of the > > station and I just kept driving until the signal dropped out. I got > pretty > > far before that happened, so I can see the potential of this service." > > > > LG Electronics, Zenith Electronics and Harris, all proponents of the MPH > > scheme, helped out with the field trials. WRAL-DT uses a Harris Sigma CVD > > UHF transmitter, with an MPH module, for the weeklong test. > > > > In a statement, James F. Goodmon, CEO of CBC, said "mobile DTV > broadcasting > > enables WRAL to better serve our viewers, communities, and advertisers by > > providing a strong combination of anywhere access, two-way communication, > > and mobility." > > > > In 1996, Harris worked with WRAL-DT as one of the first DTV stations in > the > > country. Two years later, when John Glenn made his historic return to > space, > > Harris worked with WRAL to conduct the first live HDTV broadcast of a > space > > shuttle launch to audiences nationwide. Now, the station is the first to > > promote mobile DTV service in the state of North Carolina. WRAL predicts > > that more than 200 million portable devices will be sold in 2008, > although > > few if any will have the necessary MPH reception chips inside. > > > > WRAL-TV and Capitol Broadcasting Company are part of the Open Mobile > Video > > Coalition (www.openmobilevideo.com), a nationwide group of broadcasters > > driving the deployment of mobile digital broadcast television. Commercial > > deployments are forecast for 2009. The group hopes to have an established > > standard available to broadcasters by the February 2009 analog shutoff > date. > > -- > > Tom Barry trbarry@xxxxxxxxxxx > > > > > > > > > > ---------------------------------------------------------------------- > > You can UNSUBSCRIBE from the OpenDTV list in two ways: > > > > - Using the UNSUBSCRIBE command in your user configuration settings at > > FreeLists.org > > - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word > > unsubscribe in the subject line. > > > > > > > ---------------------------------------------------------------------- > You can UNSUBSCRIBE from the OpenDTV list in two ways: > > - Using the UNSUBSCRIBE command in your user configuration settings at > FreeLists.org > > - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word > unsubscribe in the subject line. > > b‹œju > I@R úèšØ^:—§ > 5eŠËbžÜ(Á¬¬Rȧ‚Ø^PÔ" ' ¢iš اʋ«ºÇ«r‰ßŠ > «jبžÇ¶)౫Eç‹ŠËl¢¸ Êǧv)àjg¬±¨ ¶Š)zwm¾·ª¹ë-~·ž–+-²ŠàÂ+a¶ °¢·nžË›±Êâm觶 > ¬¹¸ÞrÙb > > > > ---------------------------------------------------------------------- > You can UNSUBSCRIBE from the OpenDTV list in two ways: > > - Using the UNSUBSCRIBE command in your user configuration settings at > FreeLists.org > > - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word > unsubscribe in the subject line. > > >