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DVCProHD codec is not compressing well

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Tom Brooks
DVCProHD codec is not compressing well
on Jan 4, 2010 at 10:41:28 pm

Hi folks. I don't post here often, but I'm a CC regular. Looking for info on this topic. I'm getting substandard results trying to compress a DVCProHD 720p24 (23.976) movie that was exported from Final Cut. Target is WMV, 960x540 at about 2600Kbps. I'm getting a jaggy edge that is just unacceptable. My guess is that the encoder (Compressor with Flip4Mac Pro Studio HD) is not handling the DVCProHD non-square pixels properly. If I change my sequence compressor to ProRes 422, render and use that in Compressor, it looks perfect. But that's a lot of render time. All my live footage is DVCProHD, so that all has to be rendered. Any info or thoughts would be appreciated. Thanks.
- Tom


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Chris Blair
Re: DVCProHD codec is not compressing well
on Jan 6, 2010 at 2:16:19 pm

What version of WMV are you compressing to? Versions 7 and 8 aren't very good. Version 9 (which uses a version of the VC-1 codec) is quite good and is comparable to H264 in terms of quality to file size ratios.

The non-square pixel to square pixel theory doesn't seem to fly if adding the extra DVCProHD to ProRes step clears up the issue. From my understanding of ProRes422 (from Apple's white paper on it), it can handle full-raster or partial width sources (non-square by my understanding). So going from DVCProHD to ProRes shouldn't change the pixel aspect. Hence, then going to WMV from ProRes would mean there's still a pixel aspect change from non-square to square.

I don't have an answer for you as to why adding that extra step results in a better WMV encode, unless the complexity of decoding from DVCProHD to WMV throws a wrench into the transcode.

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com


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Tom Brooks
Re: DVCProHD codec is not compressing well
on Jan 6, 2010 at 4:24:48 pm

Hi Chris,
Yeah, I'm just grasping at straws with that theory. You're correct, the ProRes422 version does have the same PAR. So it might be the WM encoder having trouble with DVCProHD. I'm going to WM9 using something very close to one of the standard presets in the Flip4mac Studio Pro HD software. It's the 2000kbps, VBR, 960x540. The only change I make is to limit the max bit rate. I'll see if I can pick up any info from the Panasonic or Telestream folks. Thanks for your thoughts.
- Tom


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Chris Blair
Re: DVCProHD codec is not compressing well
on Jan 6, 2010 at 11:02:40 pm

You're welcome. There's no good reason that I'm aware of for what you're seeing happen.

Chris Blair
Magnetic Image, Inc.
Evansville, IN
http://www.videomi.com


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