8mm Film to DVD - Is 7.5 to 115 IRE Normal?

[Eric H.]

Hello,
I have a DVD that was created from an 8mm film transfer. After ripping it to my computer, I imported it into Premiere Pro in order to analyize it using the scopes. The YC Waveform monitor shows the black/white levels ranging from 7.5 to 115 IRE. Are these readings normal? The end goal is to publish it to the web, so should the levels be 0 to 100 IRE? I've read a great deal regarding 7.5 setup and how it applies to the analog domain, but am unsure how it relates to video destined for the web.
Thank you,
Eric

[jagabo]

Setup only applies to North American analog transmission. Virtually all commercial distribution formats (Blu-ray, DVD, broadcast/cable/satellite TV) and streaming video are 0 to 100 IRE. For 8 bit YUV that's Y=16 to Y=235. Sometimes there are excursions outside that range because of oversharpnening halos (very common with VHS caps, for example) or some picture elements you don't care about (a bright light in the background, a dark corner of the frame, etc.) but you want to keep the bulk of the video within range. Certainly anything in the frame you care to see should be within range.

[Eric H.]

Thank you for the information jagabo. In your opinion, should I adjust the 7.5 to 115 IRE levels to 0 to 100 IRE for streaming purposes? I just did that as a test, and the blacks look much richer, while the overall contrast has a bit more definition, with the highlights being less washed out.

[jagabo]

In your opinion, should I adjust the 7.5 to 115 IRE levels to 0 to 100 IRE for streaming purposes?

Yes.

[Eric H.]

Thank you again jagabo. Do you think it would be a good idea to adjust the gamma levels once the black/white levels are moved to 0 to 100 IRE?

[jagabo]

I think you should do what's necessary to get the video looking the way you think it should look. Maybe upload a sample for others to give you an opinion. Changing the luma levels often also requires similar adjustments to the chroma.

[Eric H.]

Thank you for the helpful advice jagabo. Do you mean to upload a sample video clip or frame screenshot?

[manono]

When jagabo or anyone else asks for samples they mean untouched, unreencoded video samples straight from the source, 10 seconds or so.

[jagabo]

You can use Mpeg2Cut2 or DgIndex (part of DGMpegDec) to trim out a short segment(s) from your VOB/MPG files.

[Eric H.]

Thank you manono. I will remember that from now on. Regarding your advice jagabo, I don't have access to the VOB files anymore, as I imported the DVD as MPG files using Nero, and had to give the disc back. I'll take a lot at Mpesg2Cut2 first, as I've seen it referenced on other threads, but have yet to try it out.

[Eric H.]

Okay, here is a short sample, trimmed using Mpg2Cut2:
https://forum.videohelp.com/attachment.php?attachmentid=49692&stc=1&d=1564640398

[Eric H.]

Would this thread be better suited on the Restoration forum?

[manono]

The black levels should be lowered some. The white levels should be lowered a lot. They're completely blown and a lot of it can't be properly recovered. Maybe the lighting is at least partly responsible for that.

Why would anyone purposely field-blend home movies?

[Eric H.]

Thank you for the helpful advice manono. I adjusted the black level down to 0 IRE, and was able to lower the white levels down to 100 IRE without, fortunately, any issue. I raised the gamma levels slightly, which brought out some lost details. As previously mentioned by jagabo, how much change in chroma is to be expected after fairly drastic changes to luma?

[jagabo]

Sorry, I was going to experiment a bit more with your sample before replying. Then forgot about it...

I don't think you want adjust the darkest parts of the picture down to IRE 0 and the brightest parts to IRE 100. That looks too harsh to me (too much contrast). I'd shoot for about IRE 5 for the black level and IRE 90 for the white level. The idea here is that the original scene had brighter brights and darker darks but they were crushed by the film and/or capture. To keep a more natural looking image you don't want to push the existing blacks all the way down to IRE 0, but rather keep them closer to where they would have been if the darker darks hadn't been crushed. And the same with the brightest parts of the picture.