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Old June 6th, 2008, 07:56 AM   #1
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Impact on Panasonic Cameras using Mpeg-2?

Hello,

I was thinking about the XDR units and wondering what the image quality impact would be if these units were used with Panasonic cameras.

The DVCPRO HD codec is Panasonic's own and I wonder if changing to the Sony Mpeg-2 would alter the P2 cameras' "look"?

Any ideas?
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Old June 6th, 2008, 11:23 AM   #2
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Dear Tim,

I will start to answer your question. I encourage others to join in.

This depends on the specific Panasonic camera and the method used to get an HD-SDI signal out of the camera.

For the Panasonic cameras that do not have HD-SDI, such as the HVX200, the component output may be higher resolution than the signal recorded using the DVCPro HD codec. This is one of the things that we will learn when we get the Flash XDR in the field.

Wikipedia states: DVCPRO HD prefilters the 720p image from the DSP to a recorded size of 960x720, and 1080i is prefiltered to 1280x1080 for 59.94i and 1440x1080 for 50i.

The Flash XDR sends the "Full Raster" into the Sony MPEG2 compression modules.

Our testing has shown that recording "Full Raster", without any prefiltering, enhances the image. However, as you have alluded to, this may be subjective.
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Old June 6th, 2008, 11:45 AM   #3
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That's kind of the path I was thinking.

For example, with the HPX-500 over SDI, I wonder if the Mpeg-2 codec might add some detail to the image?

Although it would be interesting to test as Panasonic might have tailored the best output of the camera around their DVCPRO HD codec.
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Old June 6th, 2008, 01:26 PM   #4
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Assuming that it is a pure uncompressed 4:2:2 HD-SDI output, the Flash XDR should yield noticeably better results than the DVCProHD from the P2 card.

It would also depend on the bitrate recorded, but I would think at equal bitrates, the MPEG2 would probably look better, let alone the 160mb mode, or the 10-bit Uncompressed mode.

And the MPEG2 also won't "sub-sample" the luminance resolution like the DVCProHD codec would.

Otherwise from that, color or image shouldn't be affected as your feeding the codec the same thing.
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Old June 6th, 2008, 06:05 PM   #5
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Quote:
Originally Posted by Michael Galvan View Post
Assuming that it is a pure uncompressed 4:2:2 HD-SDI output, the Flash XDR should yield noticeably better results than the DVCProHD from the P2 card.

It would also depend on the bitrate recorded, but I would think at equal bitrates, the MPEG2 would probably look better, let alone the 160mb mode, or the 10-bit Uncompressed mode.

And the MPEG2 also won't "sub-sample" the luminance resolution like the DVCProHD codec would.

Otherwise from that, color or image shouldn't be affected as your feeding the codec the same thing.
Hi Michael-
Our own tests show the 50 Mbps Long-GOP to yield superior resolution as compared to DVCProHD (at least on a still image). As you and Dan mentioned, Flash XDR does not horizontally scale the image, but retains the full raster in both 1080i/p and 720p modes. This greatly reduces aliasing and "jaggy" lines and improves overall image quality.

In my opinion, DVCProHD was a great CODEC 5 years ago, but the industry has advanced significantly since it's inception. The Sony MPEG2 CODEC is now on it's 6th or 7th generation design and has seen significant improvement over the last few years. Note that Panasonic is now heavily promoting their AVC Intra CODEC. I wonder if they think DVCProHD is past it's prime.
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