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Old November 17th, 2007, 03:50 PM   #1
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dvcpro hd bitrates

Hi, I'm new to DVCPRO HD (from HDV) and am a little confused about its bitrate. So far I've found data that says it records at 100 Mbits/sec... but does this number not vary for different resolutions (1080p vs 720p, e.g.)? Or are smaller frames compressed less? Any clarification is really appreciated. Thanks.

Chris
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Old November 17th, 2007, 04:15 PM   #2
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Well, DVCPRO HD in the Varicam always records at 720/60P at 100 Mbps. If you shoot at 24P, then 36 redundant frames are added, since the VTR always runs at 60 Hz. I don't know about the 1080i DVCPRO HD camcorders, but they must also be limited to 1080/60i at 100 Mbps.

However, if you are recording to memory cards, like in the HVX200, you aren't limited to the speed of a VTR, so you can shoot and record 24P/720 in DVCPRO HD, which works out to be a lower data rate I believe (40 Mbps-ish I think.) Is there a DVCPRO HD camera that shoots 60P/1080? I think you're limited to 720/60P or 1080/60i, either at 100 Mbps, with that codec.

I don't think you wouldn't have a camera that was both HDV and DVCPRO HD, certainly not with a camcorder VTR, but even I doubt a camera exists that uses both codecs to memory cards, it's sort of one or the other. I could be wrong.
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Old November 17th, 2007, 04:40 PM   #3
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Hi David, thanks so much for your reply. I'm actually recording from a video source and planned to use a VTR like the Panasonic AJ-HD1400. On the spec page at Panasonic's site (http://tinyurl.com/y6brta) it says it can record at 1080p and 720p... but it just gives the 100 Mbps bit rate. I'm curious if you have any idea, based on your experience, how this would work. I know all about MPEG-2 and HDV but am totally new to this format.
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Old November 17th, 2007, 05:09 PM   #4
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Different amounts of compression can be used to fit different sized signals into the same bandwidth. 720P is smaller than 1080 and Panasonic chose the original DVCPRO HD data rate as 100MBPS related to a doubling of DVCPRO 50 to record HD.
1080 was added to DVCPRO 100 later when Panasonic was trying to compete for business with clients who wanted 1080.

The compression scheme in DVCPRO is on a frame by frame basis so it has a constant data rate. Each frame ends up as a unique bucket of data.
HDV Mpeg uses groups of frames so compression can vary from frame to frame depending on what is going on in the frame as well as frames in the same GOP. JVC is using several GOP lengths 6 and 12 frames, Sony and Canon are using 15 Frame Gops. The first frame in a Gop is a full frame and the other frames are just tracking the changes saving bandwidth.
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Old November 18th, 2007, 08:46 AM   #5
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That's very helpful ... thanks!
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Old November 19th, 2007, 11:46 AM   #6
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Quote:
Originally Posted by Chris Rehbeck View Post
Hi David, thanks so much for your reply. I'm actually recording from a video source and planned to use a VTR like the Panasonic AJ-HD1400. On the spec page at Panasonic's site (http://tinyurl.com/y6brta) it says it can record at 1080p and 720p...
Searching online, this is what I got:

https://eww.pavc.panasonic.co.jp/pro...aj-hd1400.html
Video Formats Supported by the AJ-HD1400
Recording: 1080/59.94i, 1080/50i, 720/60p, 720/59.94p, 720/50p

No 1080P recording. 1080P output though.
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Old April 1st, 2013, 04:22 PM   #7
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Re: dvcpro hd bitrates

Hello I wonder if anybody knows the Panasonic AG-HPX500 P2 HD, that records in DVCPRO HD on P2 cards.
Does it record in 1080 25p? And what is the bitrate in this setting?
I have not been able to pull out this information from the internet.
I am researching for a client.

Thank you.
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Old April 2nd, 2013, 12:41 PM   #8
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Re: dvcpro hd bitrates

Yup. On Panasonic's site.

Panasonic AG-HPX500 High Definition Camcorder - Professional Video Camera

Didn't see the bitrate listed.
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Old April 2nd, 2013, 04:32 PM   #9
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Re: dvcpro hd bitrates

This article is questioning some bitrate data...
HDCAM, XDCAM & DVCPRO HD: Some Questions Answered : HD High-End
What do you say... I'm not an expert on this.
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