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HD source color problems in MPEG 2

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Matthew Brunn
HD source color problems in MPEG 2
on Apr 14, 2010 at 6:56:25 am

Got a real head scratcher. (for me)

I have a show, two in fact, that are exhibiting some disturbing color artifacting in MPEG 2.

Mac Pro 8core i7
Mac OSX 10.5.8 FCS 2
FCS 3 and 10.6.3 (separate machines)
AJA LHi Driver 7.5

I have tried all this on my own personal system. Specs on the signature. Plus a G4 Power Book Running OSX 10.4 and FCP 5.1.4, Compressor 2.

Both Projects edited in their native codecs and then a self-contained movie produced from the timeline in that codec.

First project was captured and edited DVCProHD 1080i. The women's clothing pulsates a solid blocks of color. We had tried desaturation, multiple ways of down-converting and de-interlacing the output from FCP. The problem remained when Compressor got a hold of it. Bitrate did nothing to affect the color pulsing. This seemed to be solved with Bitvice 2.9.

Example: This the original HD clip. 78MB file.

This is the resulting MPEG2 from Compressor. I tried other codecs (h.264, Flash) in compressor and did not get the same color pulsing. 4.5MB file.

Second project was captured and edited Apple Prores 422 1920 X 1080i. I may have a related issue with this project. We had the same color pulsing issue but now there seems to be problems with the colors bleeding in the yellow text on the graphics. When the self-contained movie from FCP is down-converted to 10BIT uncompressed is compressed to MPEG2 and de-interlaced in Bitvice the text is fine. The color bleeding (for the lack of a better term) happens when we compress directly from the HD also. The down conversion seems unnecessary and HD to MPEG2 should give us our best result.

The reason for the down conversion from HD to SD it is a workflow to accommodate what looks good to the client. The client watches our final product on a sub par LCD TV and if it doesn't look there it is not good. We have given up changing their mind. Regardless, I'm not sure why we are having such an issue with these, so far, two projects.

Source interlaced 10 Bit Uncompressed

Compressor 2 pass 6.2 VBR Interlaced

Bitvice approximately same bit rate settings as above. De-interlaced

DV50 interlaced Source. This source already has issues with the text but I've had DV25 stuff look better in MPEG2 than these results below.

Bitvice interlaced from DV50 source

Bitvice de-interlaced from DV50 source

I have a growing suspicion that it may be the install of After Effects. It is on all machines that I have worked on. Thanks for your input. I'm not sure where to turn.

Hope this helps-
Quad Core i7 2.8Mhz
OSX 10.6.3
Ram 4GB
FCP 7.0.2/CS 3/DVDSP4

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