Tech Case Study: Streetwise (Part II)

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It’s Just a Phase

A long-term solution to preserve the legacy of CTW programs required careful judgment and a methodical approach. Until 1997, the CTW library, as with all video libraries, had been insured only for the cost of raw video stock and duplication.

"They never really counted their tape library as a potential money-making asset," explains Schuman. "In terms of programs, they were keeping them for historical purposes, but keeping one copy."

CTW’s board of trustees approved a restoration budget in the summer of 1998 and advanced preservation was initiated. Over 4000 hours of "Sesame Street" video and 2000 hours of additional CTW programming underwent a sophisticated cleaning and rejuvenation process thanks to media restoration experts at Vidipax. Vidipax then created two back-up libraries consisting of analog BetaSP as well as D2 (a tape standard for digital composite NTSC) copies.

Phase two of the new and improved video asset management system called for a digitization strategy to produce another library in 16MB, MPEG-2 4:2:2 studio profile. Information services senior systems developer Peter Horoszowski joined the CTW team to help usher CTW assets into our much-ballyhooed digital age.

"We use a Vela [MPEG-2] encoder, run through digital scopes. We’re actually watching the output of the encoder," says Horoszowski. "We’re watching our final product to see that we don’t exceed NTSC color values, the audio is proper stereo and make sure there’s nothing particularly out of phase."

Lest we forget, encoding 6,000 hours of MPEG-2 video requires diligence, staff and a significant time commitment. Schuman estimates the process will continue for five or six more years before completion. "But on the other hand, at least I’ve saved it," adds Schuman.

All MPEG-2 segments are transferred to 50GB tapes (soon to be upgraded to 100GB) on an Ampex DST digital storage unit. Approximately every two to three days, when a tape is full, a duplicate is created and both are check-summed to guarantee bit for bit accuracy. Once matching values are confirmed, the duplicate is taken offsite for storage.

When the Ampex system is not in use, it pulls tapes and performs check-sums. Each tape in the onsite MPEG-2 library is evaluated every two months. As Horoszowski explains, "If we’ve even lost a single bit of data, we then go back to the other tape, pull it from storage, compare and make sure."

According to Horoszowski, so far, so good. He hasn’t encountered a single corrupt tape.

Getting Video on the Desktop

Horoszowski’s custom-written development of an automated "video on the desktop" application is easily one of the team’s most impressive accomplishments to date. Once an MPEG-2 file is created, the file is encoded to 1.25MB MPEG-1 file while a .JPG storyboard of the segment is created simultaneously).

Kermit, as the Silicon Graphics (SGI) "video frame grabber" is more commonly referred to, is responsible for capturing .JPG stills based on scene changes in the MPEG-2 playback. Kermit is thereby responsible for sending the storyboard images, via FTP, to Grover, the SGI Unix server.

"The storyboarding is done with straight C and C++ and a lot of the SGI graphics libraries. The syncing of these two boxes, including the playback and the encoder, is done in Perl and C++," says Horoszowski, the resident code jockey.

Workshop intranet users can search for and access the MPEG-1 4:2:0 "low-res" clips based on query results pulled from an Oracle 8 database (see sidebar page 44). For offsite writers who need to review segments, streaming Windows Media files are currently available for 56Kbps dial-ups.

Thus far, streaming media has proven to be one of the easier additions to the digital asset management (DAM) system. "When we’re done, we want all three variations (Real, Windows Media, QuickTime)," says Horoszowski. "We have the storage space."