Originally featured on BroadcastEngineering.com
JPEG 2000 may offer new ENG solutions
An emerging wavelet-based compression algorithm may play an important role in the future of electronic newsgathering, particularly in HD ENG, because it offers efficient intraframe compression, low latency and the amount of compression applied can easily scale to available bandwidth.
JPEG 2000 has already made a splash in the digital cinema arena as the accepted standard for digital movie distribution to theaters. A few months ago at IBC2005 in Amsterdam, JPEG 2000 took center stage as the compression engine behind a viable contender for the next-generation ENG equipment — suitable for HD acquisition and transmission — with Thomson’s unveiling of the Grass Valley Infinity camcorders and recorders.
Now Analog Devices, the first company to market silicon compression engines for JPEG 2000, is taking aim at the consumer electronics market. In the process, the company has introduced an affordable, technically well-suited solution for ENG equipment.
Regardless of how the consumer market plays out, JPEG 2000 offers some attractive advantages for ENG, particularly for compressing large HD video images acquired in the field. According to Bill Bucklen, Analog Devices Advanced TV Segment Director, JPEG 2000 is an intraframe approach to compression. Unlike competing MPEG formats, there is no motion estimation. That means each frame stands alone, which offers a way to circumvent predicted delays introduced by MPEG during two-ways between reporters in the field and anchors in the studio. JPEG 2000 latency is less than one frame.
JPEG 2000’s compression output rate is deterministic. With the compression scheme, it's easy to set a threshold, such as 5Mb/s, and if conditions change making less bandwidth available, smaller file sizes are instantly available.
With JPEG 2000, a reduction in quality affects images differently than a loss in quality with MPEG. With MPEG, reduced quality leads to motion artifacts and blocking artifacts. With JPEG 2000, a reduction in quality appears softer, more like analog artifacts and little noise.
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