12.13.2006 08:00 AM
Originally featured on BroadcastEngineering.com
Author forecasts impending decline for HDV format
Industry consultant and author Tore Nordahl last week published a new analysis of the HD compression landscape that forecasts near- and longer-term success for HD camcorders that use AVC-Intra and JPEG2000 compression and the beginning of a decline for those used in ENG and EFP that rely on MPEG-2 long-GOP compression.
The long-GOP format Nordahl discusses is HDV — the 25Mb/s prosumer high-definition format that’s gained support from some broadcasters and video professionals looking for an affordable HD field acquisition solution.
In the article, “Will Panasonic's AVC-Intra/P2 and Grass Valley's JPEG2000/CF push out MPEG-2 in 2007?” Nordahl points out that about four years ago, HDV camcorder manufacturers decided to use 25Mb/s DV tape as the recording medium for the format. At the time, only a long-GOP MPEG-2 codec could deliver the compression necessary to record high definition at 25Mb/s. However, using the long-GOP codec came with a price, namely “codec cycle latency,” says Nordahl.
This latency refers to the second or more needed for the long-GOP codec to rebuild desired frames from the appropriate independently compressed frame (I-frame) and the group of pictures dependent upon it. That process can be painful in post where editors must wait for the process to occur before ingesting each desired scene into their nonlinear editors.
“So, with HDV not being intraframe, and thus more difficult to edit and manipulate, HDV by definition is a temporary format in my opinion, particularly now that nonlinear storage AVCHD consumer camcorders are shipping,” writes Nordahl.
In contrast, AVC-Intra, Panasonic’s recently announced codec, and JPEG2000, which Thomson Grass Valley is using in the soon-to-be-released Infinity camcorder, compress every frame independently “with nearly no latency,” says Nordahl. Access to independently compressed frames makes real-time ingest, editing and viewing easy, he adds.
The impact of this difference will begin to affect HDV camcorder sales in the second half of 2007, with sharp declines beginning in 2008, according to the article.
To read the article in its entirety, visit www.coax.tv/.