VideoHelp Forum

Our website is made possible by displaying online advertisements to our visitors. Consider supporting us by disable your adblocker or Try ConvertXtoDVD and convert all your movies to DVD. Free trial ! :)
+ Reply to Thread
Results 1 to 10 of 10
Thread
  1. Original MPEG2 short sample
    H264 TS file After using McTemporalDenoise and QGTMC

    It looks like clouds of noise in the background obviously caused by the original file's low bitrate. Is there any way to remove that noise with Avisynth?
    Last edited by VideoFanatic; 3rd Apr 2013 at 11:00.
    Quote Quote  
  2. Don't lighten the background so much.
    Quote Quote  
  3. OK but that doesn't really help me as the noise was there in the first place. I also had to remove the darkness blur from the background with this:
    Code:
    Tweak(Sat=0.8, Bright=10, Coring=False) 
    
    ColorYUV(gamma_y=200, off_y=-32) ColorYUV(off_u=3, off_v=-0)
    Is there no way to remove the noise apart from lowering the brightness?
    Quote Quote  
  4. The noise will be darker so you won't notice it as much. Your "after" video looks totally washed out. The black level is at ~48, not ~16.
    Quote Quote  
  5. Banned
    Join Date
    Oct 2004
    Location
    New York, US
    Search Comp PM
    No. I don't know what "darkness blur" means. The "cloud" is seriously heavy block noise and banding, caused by a low bitrate, by lord knows how many previous encodes, and mainly by crushed blacks that appear to have been "re-crushed" several times. Crushed colors means that data below a certain darkness value has been destroyed. You'll see that the edges of the fluttering cloud are all darks with no smooth gradations between darker and lighter shades. You need a lot of deblocking filters and some grain. Much of the banding will return when you re-encode.

    Ratrher than use QTGMC, I had better luck with:

    Code:
    AssumeTFF().SeparateFields().TemporalDegrain().Weave()
    Follow that with whatever you want to clean up edges on the figures and smooth out those thick blocks and banding, which won't be easy and won't completely go away. Brightening crushed blacks won't make them cleaner, it just makes them a lighter shade.
    Last edited by sanlyn; 26th Mar 2014 at 07:59.
    Quote Quote  
  6. Banned
    Join Date
    Oct 2004
    Location
    New York, US
    Search Comp PM
    I seem to recall a Doom9 post that fiddled with needi3 resizing + slight blur + denoise + dither + sharpen/restore size, without appreciable detail loss but with consierable reduction in excessive banding and block noise. Spent almost 2 hours looking for that post just now. Seems I lost the old copy of one or two pages in that post, from 2 or 3 years ago. I've seen something like this mentioned in Photoshop forums, too. Anyone familiar with such methods? If not, so be it. I'll keep looking.
    Last edited by sanlyn; 26th Mar 2014 at 07:59.
    Quote Quote  
  7. Originally Posted by sanlyn View Post
    No. I don't know what "darkness blur" means. The "cloud" is seriously heavy block noise and banding, caused by a low bitrate, by lord knows how many previous encodes, and mainly by crushed blacks that appear to have been "re-crushed" several times. Crushed colors means that data below a certain darkness value has been destroyed. You'll see that the edges of the fluttering cloud are all darks with no smooth gradations between darker and lighter shades. You need a lot of deblocking filters and some grain. Much of the banding will return when you re-encode.

    Ratrher than use QTGMC, I had better luck with:

    Code:
    AssumeTFF().SeparateFields().TemporalDegrain().Weave()
    Follow that with whatever you want to clean up edges on the figures and smooth out those thick blocks and banding, which won't be easy and won't completely go away. Brightening crushed blacks won't make them cleaner, it just makes them a lighter shade.
    OK thanks. I'll try that. You're correct that video didn't need the gamma setting, I'm not sure why I thought it did - it seemed like it added more detail when looking at it in AvsPmod. However without the gamma setting the video looked much better and I can't see much noise. I'll try that script you mentioned as well.
    Quote Quote  
  8. Banned
    Join Date
    Oct 2004
    Location
    New York, US
    Search Comp PM
    I followed TempralDegrain with MCTemporalDenoise, Deblock, and GradFun2DBmod. You can't try to overly smooth that noise, it just comes back looking worse during encode. The video itself has somewhat darkish blacks, so I'd maybe use tweak or soemthing to raise the black just a small amount (I lowered contrast a bit with ColorYUV(cont_y=-20), which was just enough to get blacks up to RGB16. You certainly don't want any more contrast, as facial highlights almost look on the edge of burning out. This kind of block garbage is really difficult, especially if it's been encoded previously, and YUV->RGB->back to YUV makes it worse as well. Usuaslly you have bto put up with grain to mask that stuff; use too much more degraining than TemporalDegrain, and the hard edges return. TemporalDegrain helped get rid of most of those big "dancing" clumps of noise.

    That resize/denoise/restore I've seen has worked, but I've two PC repair clients just now and can't try it yet.
    Last edited by sanlyn; 26th Mar 2014 at 07:59.
    Quote Quote  
  9. OK thanks. Is it safe to use TemporalDegrain in addition to McTemporalDenoise medium and QTGMC or will TemporalDegrain just smooth more, losing detail?
    Quote Quote  
  10. Banned
    Join Date
    Oct 2004
    Location
    New York, US
    Search Comp PM
    Using all three would be overkill, with unnoticeable gain. TemporalDegrain isn't that much of smoother, it's a strong denoiser. I'd follow it with MCTemporalDenoise (I used "high") plus DeBlock() and GradFun2DBmod. DOn't forget there's a nice denoiser out there that also does some block and chroma cleanup (DftTest), but it has a softer look compared to TemporalDegrain. For me, QTGMC would make the blocky edges and banding look more distinct, which is undesirable, even with QTGMC's sharpening turned down (and turned down far enough, QTGMC looks blurry).

    You can try all this stuff, just use a few seconds of video and check it out. Using all 3 would definitely over-filter, but sometimes that's the only way to get rid of everything. The problem is, some of the "detail" you see has a lot of noise in it. The more noise you remove, the more detail you lose. You have to judge how much imperfection you can live with. There comes a point where you can get a bad video so clean there's nothing left to look at.

    I see many ancient, classic movies restored on Turner Classics. You'd be amazed how much rotten garbage they leave (including projector scratches and rotted edges, etc.), but judging from what's left of the original oldie, going any further would destroy too much.
    Last edited by sanlyn; 26th Mar 2014 at 08:00.
    Quote Quote  



Similar Threads