PDB - just wondering if you could give an overview of how you ‘clean up’ mpeg2 HDTV sources please? I’ve a few I’d like to work on and was interested in how you go about it.

(2019-09-04, 07:45 AM)alexpeden2000 Wrote: PDB - just wondering if you could give an overview of how you ‘clean up’ mpeg2 HDTV sources please? I’ve a few I’d like to work on and was interested in how you go about it.

Well I'm no expert (smarter people have helped me) and you might already know all this but here it goes.

For Mpeg2 HDTV sources, talking 1080i/29.97, I always run them through DGMPGDEC to check the stream for flag changes and load the resulting d2v into avisynth.

In avisynth run TFM and TDecimate to get the video back to 1080p/23.976. For progressive PAL encodes might need to use assumeFPS (or sometimes changefps) to slow it down to 23. The mess that is masters that are conversion from NTSC to PAL done poorly is its own subject.

Pretty much every Mpeg2 HDTV file I have ever seen has some degree of macro-blocking which is exasperated by a lot of countries using too low of bit-rates (say anything under 20 for Mpeg2). For macro-blocking, I use Deblock_QED. Deblock_QED default settings (I think 24?) should smooth over about 75% of the problems. For the rest you probably then need to check on fast moving action scenes or any scene with flash/pulsing lights as those are difficult for Mpeg2 encoders to deal with in low bit-rates.

For example, in Conan the scene of the approaching horses to the battle of the mounds had an excessive amount of blocking. All the moving horse legs, pointy armor and ground moving past the camera was too much for the encoder. So I had to up the settings there. You lose a little detail for a stable picture. You just have to be careful not to go too high or it turns the picture into mush. Also, sometimes, a good anti-aliasing filter on low settings or an one way edge blur can ease the blocky edges

Some HDTV broadcasts also still have halos/EE/over-sharpening. Particularly older masters. It's less a problem now but when I do see it, I use DeHalo_Alpha. The default settings are ok. You just have to play around until you get rid of the most amount of halos as possible. Anything left might be able to be cleaned up with another plugin to do slight edge blurring or re-graining if the project needs it.

After that if you want to do some noise removal I love QTGMC. It has a list of denoisers a mile long. Each with their own settings. Personally, I like EZkeepgrain as I always want to keep natural grain or noiseprocess when there is no grain to care about. Some of these denoisers will also help remove compression artifacts in AVC/Mpeg4 encodes.

Mpeg2 generally just falls apart when it can't encode something, Mpeg4 sometimes cheats by using smaller blocks (keeping with its block size matrix) or smooths over textures all together. Removing compression artifacts is also it's own subject (like Top Gun) and one that's there is no one answer for that. Regardless, you don't have to do noise removal, it just depends on the HD master.

I sometime sharpen. That's also optional but its often a good way to offset the above work. Its best to find a sharpener that produces as little halos as possible like msharpen or limitedfastsharpen. If using msharpen you can use the mask setting to see what you are getting. Best to do as low as possible, particular at a point that the grain doesn't get sharpened. That makes the video look artificial.

And for avisynth you have to make sure you do all the colorspace conversions are done right, Rec709, YU12, RGB, all of that.

At that point I usually take the work into a NLE. I'm a Premiere (AP) guy and like it the best for simpler jobs like Conan. More advance color work gets put into Resolve. AP's color correction is made better if you have some of the Red Giant plug-ins like Colorista4 as an example. I just like doing color and grain work in AP over avspmod since the results are easier to analyze with AP's zooms, scopes, etc. Avisynth/avspmod has those tools but they are rougher to use, IMO.

The advantage of avisynth is it has specific tools that mitigate the above issues. AP has very few (sans plugins), AE has some more and Phoenix the most.

For Conan, I also had to plug in missing frames from another HDTV broadcast and aligning the HBO broadcast to get the mono soundtrack from that. All of that is easier in a NLE.

Anyway that's just my stream-of-conscious prattling. Hope it helps

Wow, a lot of great stuff in there - thanks PDB. I really need to get round to learning Avisynth (along with Resolve!)

One quick question, what program do you use for patching in missing frames?

(2019-09-05, 04:14 PM)alexpeden2000 Wrote: Wow, a lot of great stuff in there - thanks PDB. I really need to get round to learning Avisynth (along with Resolve!)

Hope it helps

(2019-09-05, 04:17 PM)alexpeden2000 Wrote: One quick question, what program do you use for patching in missing frames?

I was just cutting out parts from another HDTV broadcast and putting them in the better HDTV in Premiere. The best HDTV had 2 jumps of missing frames.

Which Mono is better: HBO or LD?

I think they are pretty similar. Bronan did a quick look here:

https://fanrestore.com/thread-2732-post-...l#pid54680

And thought HBO had less noise reduction.