Another HD Codec
Every time I learn of a new codec, I’m surprised. I always get that feeling that I should have heard of it before. And I got that feeling again when I learned of a new codec to be used by the Digital Cinema Initiative (DCI) called JP2K. JP2K is short for JPEG2000, and it does not process several video frames for compression at once like MPEG2 and MPEG4 do. Since JP2K processes each frame individually, it is better for real-time HD encoding than MPEG, and has less obvious and objectionable artifacts as well. Not only that, there are no licensing fees, nor is it as difficult to implement in hardware than MPEG. And it’s highly scalable, with one bitstream being viewable from a cellphone up to an HDTV.
Seeing all these JP2K advantages makes me wonder if it will be used by HD-DVD or Blu-ray one day. There doesn’t seem to be any obvious benefit for BD-ROM, but for BD-R and especially BD-RE, it looks like a great codec.
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August 30th, 2005 at 2:09 pm
The requirements to play back the JP2K vide are super high. That would be the reason you have never heard of it. No one can really play it. If you had a specialized hardware solution it could be possible in the next few years but it isn’t a codec for now, just the future.
August 30th, 2005 at 2:20 pm
Well I just read that article and it says it is cheaper than MPEG. The article probably knows best. I still think that it is very computationally expensive.
September 1st, 2005 at 9:24 am
Author - as Elvis pointed out, JP2K has extremely higher requirements. For example, on my dual 2.5 GHz G5 with ATI XT 800 card, HD plays at just a handfull of frames a second using JPEG2000. Also, at the quality (and therefore datarates) the DCI is talking about, there will be NO visible artifacts for the audience watching on a theatrical screen. I think they are talking about data rates in the 20-30 MB/sec range - hard drive speeds, not optical disk speeds.
The reason that the DCI is using it is to get pristine image quality for theatrical presentation.
It’s pure “no frame to frame compression” approach was to avoid artifacts. By definition, this increases the bandwidth required. It makes for a good theatrical viewing image quality, but the data rate (and thus quantity of data) is far, far too high for affordable optical media.
-mike
September 1st, 2005 at 9:33 am
Thanks guys! It looks like the DCI chose this codec probably for these very reasons.