ATSC Floats PSIP Standard

DTV protocol would ease intro of virtual channels, EPGs

The Advanced Television Systems Committee took a step towards making broadcasters' implementation of DTV services easier with the approval of a new candidate standard. Presuming manufacturers agree, the Programming Metadata Communication Protocol should streamline the Program and System Information Protocol (PSIP) data compilation process.

PSIP information is an important part of DTV. It tells the receiver how to divide an incoming DTV signal into different channels and includes caption information and the electronic programming guide that informs DTV viewers where to find content.

"Without PSIP, the DTV signal can't provide a program guide or even the proper virtual channels, so it's important that the PSIP information is full and accurate," says Graham Jones, manager of communications engineering in NAB science and technology. Jones is also chair of the T3/S1 ATSC specialist group on PSIP metadata communications, the group assigned with developing the communications protocol in December 2002.

The specialist group, chaired by Jones, included 20 participants, from broadcasters including CBS and ABC and manufacturers such as Decisionmark, Encoda, VCI and Triveni. The NAB and Nielsen also participated in the 23 meetings it has held over the last year.

"We had a good selection of manufacturers and we believe we're over the number needed for critical mass that will allow this to become an industry standard," says Jones. "Broadcasters like open standards."

The new protocol means broadcasters can be confidant that the disparate parts of a broadcast facility will be able to share PSIP metadata more easily.

Current PSIP generators often requires a person at the station to input the metadata. That data is then tied in with programming descriptor content from companies like Storer Associates, Tribune or Decisionmark and information from the traffic or automation system on what channel and when the content will appear. That heavy reliance on manual entry can often lead to error or PSIP information that isn't as deep and informative as it could be.

"When you have multiple sources feeding one device the best thing to do is to have a standard," says Lowell Putnam, president and CEO of VCI, a broadcast and cable traffic system manufacturer.

Putnam says one of the keys to the openness of the standard is its reliance on XML, or eXtensible Markup Language. The XML standard allows information to be read by humans and machines

Putnam says that XML will make it easier for one manufacturer to enhance its PSIP offering and, in turn, easier for others to make sure their products remain compatible.

"PSIP will more likely to be successful because you won't need all of the vendors learning to write different things in different ways to different systems," Putnam says.