Dalen Johnson
September 29th, 2005, 12:53 AM
so it has been made clear that you get uncompressed HD from the panasonic out only through analog.
Am I also correct that you get uncompressed HD directly in the camera if you record directly to the P2 card?
Kind Regards
dalen
Chris Hurd
September 29th, 2005, 01:13 AM
Hi Dalen,Am I also correct that you get uncompressed HD directly in the camera if you record directly to the P2 card?Sorry, no; on the P2 card it is always compressed. You have a choice of recording several flavors of video from DV (at 5:1 compression) to DVCPRO HD (at 6.7:1 compression). See my P2 Card Capacities chart located at: http://www.p2info.net/articles/misc/p2cardcaps.php
Dalen Johnson
September 29th, 2005, 02:39 AM
So if the HD is compressed from the Panasonic 200 onto the P2 card, what advantage is this over Canon HDV being transferred onto tape?
They both loose quality and are not uncompressed.
Is the difference frame resolution?
kind regards
dalen
Mike Marriage
September 29th, 2005, 04:10 AM
So if the HD is compressed from the Panasonic 200 onto the P2 card, what advantage is this over Canon HDV being transferred onto tape?
They both loose quality and are not uncompressed.
Is the difference frame resolution?
You are confusing uncompressed with LESS compressed.
HDV uses a lower bitrate than DVCPROHD, and in order to do so has to use higher compression. It also uses interframe compression, where it compresses using a group of pictures (GOP) rather than individual frames like DVCPROHD. This makes HDV more efficient, but requires more processing power to edit. It is also the reason that under some extreme motion conditions or where every frame is very different to the last (for example a crowd jumping up and down and waving banners at a football match), HDV can struggle and compression artifacts can show up.
Despite the lower bitrate, HDV does actually record at a higher (luma/B&W) resolution than DVCPROHD.
720p ----- HDV = 1280x720, DVCPROHD = 960x720
1080i ----- HDV = 1440x1080 DVCPROHD = 1280x1080
BUT... DVCPROHD has a higher colour resolution because it uses 4:2:2 instead of 4:2:0 like HDV. This means it records colour at 1/2 the luma resolution and HDV records it at only 1/4 of the luma resolution. This makes a big difference if you are doing heavy post work like blue/green screening. In normal conditions, the human eye has trouble seeing the difference in colour resolution, that is why it is such a common form of compression.
DVCPRO HD is a more capable format generally, but HDV does hold a few advantages, the big ones being that it is very cheap to record to tape and store on hard disk. HDV uses between 2.1 and 5.3 times less space than DVCPROHD does to store digitally.