Reversing Colorization

[abcedem]

Since there has been recent discussion on colorization of movies, I have a question on this topic. I have an mpg capped from turner classic movies of a film that's been horribly colorized and I want to get it back to b&w.

Is there any way to turn it b&w without having to convert it from mpg to avi?

[jtoolman2000]

Yes you can remove or decolorize it. The problem is that nce you create any change you will have to reencode it. You could load MPG onto say Vegas and use one of the video filters to remove all color. Then you have to export
(Reencode) back to MPG or whatever other format you wish. Will you loose quality? Maybe, maybe not. It all depends how you aproach it.

[Cornucopia]

Easy. They (normally) never mess with the luminance, so all you have to do is lower the saturation/chrominance to 0.
This can be done with Virtualdub or AVISynth, or any other NLE for that matter.
Or, you could just apply a custom colorcorrection filter (in TMPGEnc, for example) or similar effect. Or, if you have an encoder where you can fine tune the Quantization matrix, you can just apply a standard matrix to the "Y" portion, and set the "U" and "V" portions to all 0's (or whatever "Null" is).

OR

You can just turn the color down on your TV set temporarily while you're watching that show.

Scott

oops, missed the "without having to turn it from mpg to avi" part. Maybe you can change the matrices in Restream?...

[dphirschler]

AviSynth

v=AviSource("C:\work\test_movie.avi")

v=v.tweak(sat=0)

return v

Darryl

[guns1inger]

As a variation on the script above, replace v=avisource() with

LoadPlugin("path to dgdecode.dll")
v.Mpeg2Source("path to mpeg file")

and you can frameserve your demuxed mpeg video stream straight through to your encoder without having to go avi in between.

[edDV]

Just turn down the chroma saturation on the TV, or pull the PbPr cables.

The damage was done upstream. A quarter (4:2:0) to half (4:2:2) of the bitrate went to chroma.

[abcedem]

Thanks for the input everyone.

I typically author my dvds then use DVD Rebuilder to fit onto DVD...

Would I be able to just plug in the 'tweak(sat=0)' command into DVD Rebuilder under the AVS -> Advanced Expert Options -> Filter Editor?

[manono]

Yes. If there's a real colored logo before the movie plays, then to keep it colored but greyscale the movie itself, you'll combine the Tweak command with the Trim command.

Tweak is a filter built into AviSynth, so you don't have to load the plugin.

'

[abcedem]

Thanks...I didn't mean "plugin"...I just mean that I'll type in the tweak command in the filter editor.

[abcedem]

Thanks again to all for helping out....I learned a lot from just this little exercise and the solution turned out to be simpler than I thought it would be. The tweak command in dvd rebuilder did the trick! No more of that nasty color.

[manono]

Good, I'm happy to have played a small part in sending you on your way. Don't forget to remove the Tweak command from the Filter Editor, or your next movie will be B+W too.

Thanks for reporting back.