de-colorizing?

[AlanHK]

I'm backing up a DVD of a 1940s movie. It was originally in B/W, but this version has been colorized.

Is there a way to remove color from MPEG without reencoding?

I know how to filter in VirtualDub or Avisynth, but I'm looking for a simpler way.

[edDV]

You can temporarilly turn down saturation in the overlay settings.

[AlanHK]

You can temporarilly turn down saturation in the overlay settings.

Using what software?

[guns1inger]

Overlay settings are usually controlled by the gfx card drivers, or the playback software.

However I assume you are looking for a solution to include during the backup so you have a b&w DVD. In that case I suspect you either have to re-encode, or turn down the colour on your TV while you watch the video.

I seem to recall a process that someone once discussed that would allow certain processing of the video to occur without re-encoding, including basic colour, brightness and contrast adjustments. However I can no longer find any information on it, so perhaps it was just theoretical.

[cyflyer]

whats the movie ? out of curiosity...

[JohnnyMalaria]

I seem to recall a process that someone once discussed that would allow certain processing of the video to occur without re-encoding, including basic colour, brightness and contrast adjustments. However I can no longer find any information on it, so perhaps it was just theoretical.

You may be thinking of our software but it works with DV. However, the same principle could be applied - basically, set all the chroma DCT blocks to zero chroma* (this could be done without having to decompress the GOP). If that isn't possible, the next best option would be to decompress the MPEG2 and process it in the YCrCb domain rather than RGB. In this case, just set all the chroma components to 128 (for 8-bit).

Ultimately, the easiest thing is to just turn the color down on the TV (that's what I do because I find colorized B/W films revolting).

* technically 128 for 8-bit. The 8 x 8 DCT blocks would be:

128 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0

[guns1inger]

I know yours does it, but I remember, several years ago, someone discussing the same technique for mpeg-2 footage.

[AlanHK]

whats the movie ? out of curiosity...

"Destination Tokyo", 1943, Cary Grant.
A bit corny, but 10 times better than "Pearl Harbor".
I got a bit suspicious at the flesh toned faces on often grey backgrounds, and looked it up to find it was indeed shot B/W.

Anyway, I was hoping for a simple hack to just keep the luma in the MPEG, zeroing the colour, which I assume is theoretically possible, but it appears no one has actually coded such an app.

I'll just have to do it the "hard" way, by turning down the colour on the TV.

[redwudz]

Just a general question, but I've wondered if you convert a colorized video back to B+W, will it appear 'exactly' the same as the B+W original version, or does the color conversion damage the overall grayscale levels?

[AlanHK]

Just a general question, but I've wondered if you convert a colorized video back to B+W, will it appear 'exactly' the same as the B+W original version, or does the color conversion damage the overall grayscale levels?

I suppose you'd need both versions to tell.
But I remember when Ted Turner introduced colorizing in his library he said that you could just turn down the color and see the original greyscale.

[guns1inger]

It depends on which techniques has been used. Most of the (semi)automated processes, such as those used by Legend Films, are based on the luma of the source, so turning down the colour on your TV should get you pretty close to the original. I have a few of Legend's discs, which contain both the restored b & w versions and the colourised versions, and the luma is pretty consistent across both.

However some of the earlier techniques weren't so kind, so the results won't be quite the same.

[pepegot1]

If I rememeber correctly, you can do this with Videostudio 11. Just adjust the color menu and encode.

[cyflyer]

[quote"=AlanHK"]"Destination Tokyo", 1943, Cary Grant.
A bit corny, but 10 times better than "Pearl Harbor". [/quote]

I don't think its corny, in fact I have that movie also ! I didn't realise there's a colorized version released as well as the b/w, mine's the b/w. As I'm a fan of colorised movies I'm tempted to offer you a trade !!!!

You probably have 'Thirty seconds over Tokyo' also which was also recently released (in original b/w !)

[vhelp]

... happy holiday everyone

Hi AlanHK,

Well, you know.., I've been playing around with a some B/W stuff, but nothing that
serious. And in recent analog cabletv capture, I was toying around with the B/W
movie 'its a wonder life'. And while I was playing around with it, I was messing around
with the color components, r/g/b, (in one of my RGB/YUV tools) to see how much of a
difference I could do to it to push the levels up. Anyway, LSS, I set all the color
components to RED, and would you believe that this modified version did not change
from the original version. IOW, they both looked the same. I thought that it would
either come out too dark or too light or noisy, but it didn't. So, it got me to thinking
(colorization techniques and things) that it would be interesting to mess around with
an old B/W (classic) movie that was colorized that then see what would come of it.

Over last weeks x-mas holiday, I taped (yes, and in EP mode, hehe) the classic movie,
'March of the wooden solders', only to find out that they had this version colorized. I
did not know that they were going to air that one. Anyway. Some things struck my
curiosity.., like the quality and grainularityness and a few other things. I found that
particular "master" was done very well. No noise, and clean, and no mpeg artifacts of
any kind -- it was viewed on a HDTV set -- and it was a copyright (c) 1991 process.

So, after reading this article here, I thought about exploring that source (after I capture
it from [good quality] vhs tape) and my great JVC S-VHS HR-S3910U vcr, but then I found
that, hay, I don't have the B/W version -- dahh!

Still, it's all very interesting.

But, have you tried this.. using AVIsynth to open it as an mpegsource() or directshowsource()
and then using one of the many color filters, adjust it to your liking, and then feeding that to any
of your favorate sw players ??

Try it and see what happens. Set one of the channels to RED or whatever.. the sky is prob
the limit. Anyways, good luck.

-vhelp 4484

:P *~*!*~*!~* HaPpY HoLiDaYs *~*!*~*!~*