DVD-RB and CCE - brightens final output?

[phædrus]

I had an open thread at the DVD-RB site, but it appears the forum is not working over there -- I can't access the English forum with either Firefox or IE. So I will ask my question here.

Awhile ago, "crespo80" posted (probably in the CCE forum) about getting a slight brightness gain in his CCE encodes. This is something I never noticed using DVD2SVCD/CCE to back up DVD to SVCD. However, I immediately noticed it when I commenced using DVD-RB Pro with CCE. This was confirmed by the moderater "Rockas"(?) on the DVD-RB forum -- he had noticed it too. It is not so much a problem except in scenes that are already very bright -- some details get completely obliterated in the "whiteout" areas.

It was suggested I use another encoder as a solution. I don't entirely object to that suggestion, but I'd like to know why CCE appears to be brightening things with DVD-RB when it never did with DVD2SVCD.

In the earlier thread started by crespo80, it was suggested to him that it was a colorspace problem, but I have to say that until now I was blissfully unaware of YUY2, YV12, RGB etc. in the process of backing up videos. I've been using default settings on DVD2SVCD, Gordian Knot, VirtualDubMod, DVDShrink, but colorspace it hasn't been an issue until now. I never had cause to try anything fancy.

Long story short, what will happen in DVD-RB if I "turn off 'try decoding in YUY2 format'" in CCE settings, as was suggested to crespo80? Might that improve this brightness problem (which frankly appears to be clipping, or what I imagine that clipping would look like)? :)

I know the obvious answer is "just try it" but frankly I don't like mucking about with settings I don't understand. So I seek counsel.

Yes, I can try one of the other codecs included with DVD-RB, but I wouldn't be able to do a proper comparison between CCE and those other codecs if I can't solve the "whiteout" problem with CCE. (I used 2.50, but crespo80 said he used 2.50, 2.62 and 2.67 and it was all the same.)

[jdobbs]

DVD-RB does nothing to "brighten" the picture when using CCE. I've done hundreds of encodes and never noticed any "lightening" -- but everybody sees things differently so I'll show you how to adjust it.

Also, you can't turn off YUY2 encoding for CCE... it is required for it to work and DVD-RB will override it.

I don't know who said to use a different encoder -- that's just silly. If you want to adjust the picture, there are filters to do just that in AVISYNTH. Use the "Tweak" function.

You could darken a little with this filter:

Tweak(0,1,-10,1)

Below is Tweak's description borrowed from the AVISYNTH documentation.

Tweak (clip, float "hue", float "sat", float "bright", float "cont", bool "coring")

This function provides the means to adjust the hue, saturation, brightness, and contrast of a video clip.

Hue: (-180.0 to +180.0, default 0.0) is used to adjust the color hue of the image. Positive values shift the image towards red. Negative values shift it towards green.

Sat: (0.0 to 10.0, default 1.0) is used to adjust the color saturation of the image. Values above 1.0 increase the saturation. Values below 1.0 reduce the saturation. Use sat=0 to convert to grayscale.

Bright: (-255.0 to 255.0, default 0.0) is used to change the brightness of the image. Positive values increase the brightness. Negative values decrease the brightness.

Cont: (0.0 to 10.0, default 1.0) is used to change the contrast of the image. Values above 1.0 increase the contrast. Values below 1.0 decrease the contrast.

coring = true/false (optional; true by default, which reflects the behaviour in older versions) is added. When setting to true is means that the luma (Y) is clipped to [16,235], and when setting to false it means that the luma is left untouched. [Added in v2.53.]

[jptheripper]

this isnt a 7.5 vs 0 ire things is it?

[phædrus]

DVD-RB does nothing to "brighten" the picture when using CCE. I've done hundreds of encodes and never noticed any "lightening" -- but everybody sees things differently so I'll show you how to adjust it.

I don't think I'm completely off my rocker. But I'll go back and try to compare frames to establish that it is doing something. Maybe it isn't brightening the whole frame -- only washing out the areas that are already bright so that the frame appears brighter, even though brightness in other areas of the frame are not affected. So I will defer to your statement until I can definitely prove otherwise. Again, your mod on the official forum did not argue with me, so we're seeing something.

Also, you can't turn off YUY2 encoding for CCE... it is required for it to work and DVD-RB will override it.

Although I really don't understand colorspace, I thought this was probably the case from what I read on the aforementioned thread. Thank you.

I don't know who said to use a different encoder -- that's just silly. If you want to adjust the picture, there are filters to do just that in AVISYNTH. Use the "Tweak" function.

This is helpful. Even if it doesn't cure the "washout" effect I'm seeing, it could be useful in other instances.

It was your mod on the official DVD-RB forum who suggested I just use the HC encoder instead. I don't object to trying it, and see what happens. But I would like to know the cause of what I'm seeing, if it is brightening, or just an effect of the codec washing out detail to save data.

I really like DVD-RB, and I look forward to learning how to use it more effectively.

[Boulder]

ColorMatrix might help you. If the original video was encoded with different coefficients than what CCE uses, the brightness will be different in the encoded video.

CCE 2.70 uses rec.601 coefficients AFAIK, the older versions apparently use rec.709. Most other MPEG2 encoders use rec.601 as well.

At the moment you can't automate the process (i.e. ColorMatrix would be applied only when needed), that option came available in a later DGIndex version than what DVD-RB uses.

For more info, search for ColorMatrix in the Avisynth usage forum.

[Rockas]

Sorry for the late reply... my Internet connection is down for 4 days now... yes I paid the service :D
It was suggested I use another encoder as a solution. I don't entirely object to that suggestion, but I'd like to know why CCE appears to be brightening things with DVD-RB when it never did with DVD2SVCD.
I think you misunderstood me... when i said that it was just a little joke:
In your place, I would give HC Encoder a shot :)
... that's why people use smiles :) - on the other hand, HC Encoder has saved me from bad results more than once... It is really a great Encoder and free... at this point I only use my CCE 2.50 when I really need some fast encodes.
Now back to the point... yes I confirm... it happened to me more than once... CCE 2.50 (that's the one - I payed for and I usually use when I use CCE) sometimes gives me brighter results than the original... but I got that results even If I use the Encoder directly without Rebuilder or DVD2SVCD... but that not just that... I sometimes notice some "colors changes" too... the result comes with less vivid colors, at least to my eyes.
Just to make sure, I usually use RME to make some little tests to compare the encodes done by CCE 2.50 and HC, and believe me.... I can say that 30% - 40% of the times there are noticable differences... the "error" can be on my eyes (I'm not getting younger lol) but those are the eyes I use to see my movies :D

keep it UP

[phædrus]

I don't like eating crow, but in this case I am going to eat just a taste of it anyway.

Last night I took a half hour and ripped a VOB from the original disc and compared it to the VOB from the DVD-RB/CCE backup. I opened them in VirtualDubMod and saved single frames as .bmp files, and compared the original to the copy side by side. Frankly, most of the problem I'm complaining about was in the original. I just didn't remember the original was as bad as it was (in this case, the opening scenes of Ghost World, which has clips from a Bollywood movie intercut with scenes filmed for Ghost World). The Bollywood clips kind of flared out in the white areas.

The only difference I could detect in these specific frames was that the CCE backup appeared to have just slightly more contrast, which made the bright areas a little more starkly white by comparison. Also the colors were just a bit shifted. A tiny bit.

I thought a few other backups turned out a bit brighter too, but I haven't compared individual frames yet.

Rockas, what you say about the HC encoder certainly encourages me to give it a try. What quirks have you found it to exhibit, besides taking longer to encode? Really, time is not much of an object with me. I set the encoding to work, and then come back the next day, so it doesn't matter that much whether it is fast or slow (within reason).

[Boulder]

The only difference I could detect in these specific frames was that the CCE backup appeared to have just slightly more contrast, which made the bright areas a little more starkly white by comparison.

Try ColorMatrix ;)
Also the colors were just a bit shifted. A tiny bit.
Possibly caused by the unavoidable YV12->YUY2->YV12 conversion, especially if it was done mistakenly with interlaced upsampling (i.e. the video was flagged as interlaced but actually is of progressive content).

[OvERaCiD23]

I've noticed this in backups for the past 2-3 years, but the difference isn't quite subtle. I agree the difference is in contrast not overall brightness. This is using CCE SP v2.50-2.70.whateveritisnow.

[phædrus]

I just downloaded the ColorMatrix plugin. So we'll give that a try. Seems like it would be helpful for CCE backups.

Now, ColorMatrix() should be used when I do DivX encoding of DVD also, should it not?

This stuff is all new to me, and mostly Greek too. :-)

[Boulder]

Why don't you try it out? Encode a sample clip with ColorMatrix(), one without. Compare the output to the original.

For checking what coefficients your version of CCE uses, encode a sample clip and create a d2v project file with the latest DGIndex version. Open the d2v file in Notepad and see what colorimetry value it reports. The ColorMatrix docs shows you the correct place to check. Values 1 and 5 mean that it's BT.709; 2, 3 and 4 mean that it's BT.601. DivX/XviD clips use BT.601 coefficients AFAIK.