TIVTC - Artifacts?
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So, I have a bunch of music videos on DVD that I'm converting to MP4. The vast majority from this particular subscription service (Promo Only) are film sources telecined for DVD distribution.
I get good results with TIVTC using default settings on most videos. However with some, after using tfm() and tdecimate(), I get stripes of color every 4th frame in portions with faster motion, like the following: http://www.digitalfaq.com/forum/atta...1&d=1491869324 Notice the orange-ish stripes in the upper left of the frame, and also the blue regions on T.I.'s face... Workflow: Rip DVD to "IFO" mode using DVDecrypter Split VOB for specific music video using Mpg2Cut2 Create D2V file with DGIndex (Field Operation > "Honor Pulldown Flags") Avisynth Script: Code:
LoadPlugin("C:\Program Files\Video Editing\DGmpegenc\DGDecode.dll") Any ideas??? |
A few problems with your script, other than the current madness that compels people to endure a quality hit by resizing and resampling standard def source and then hollering about the results, LOL! (but I realize they're doing this for very limited playback devices or web mounting that can't handle DVD, MPEG, telecine, or other standard commercial formats):
Your code converts DVD source (which is aleady YV12) to YV12 ? ? Of course, nothing happens on that line. The statement "nnedi3_rpow2(rfactor=2, cshift="spline64resize", fwidth=960, fheight=720)" involves three resizing operations, one of them a 2x software upscale, followed by a software downscale back to nonstandard 960x720 and an alteration of the original image proportions, then a hardware resampling by your playback system to match the resolution of different display panels. Personally I would have left the original alone and been satisfied with only a one-time playback resampling. When playing on TV. did you turn off your TV's overscan feature? Otherwise you're losing part of the image by masking on all four edges on TV's with default overscan settings. Of course on a PC player it won't matter. The image posted says you have more periodic color problems than you realize -- I see a lot of discoloration and blotching in that image. The trouble is here: Code:
Crop(14,6,-14,-6) You could clean up the script by first eliminating the LoadPlugin statements, which you don't need because the dll's you're loading are in the default folder and will load automatically (unless you have some system problems that require those lines). Then, if you must, you should crop after IVTC, not before: Code:
SetMTMode(5,6) If you still have the color problem you have a faulty source. But no one can tell from a still image alone, they can only guess. |
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Thanks for your help and advice, Sanlyn. |
Yes, I figured there were special playback considerations.
The YV12 line doesn't huirt becauase the source is already YV12. The statement just doesn't do anything. No harm done, just saves some typing. Quote:
The mod-4 rule for vertically cropping YV12 applies to interlaced frames. Telecined frames are interlaced structures. But after IVTC the frames are progressive, so mod-2 can then be used. Unfortunately you likely won't get an error mesage unbless you try to use odd numbers or attempt to use a function that expects mod-4 or bigger. Many Avisynth filters will throw an error if the frame dimensions can't be cut down to mod-8 block sixes. Quote:
The DAR appears to be 16:9. If the height is to be 480, then 1.77777778 x 480 would be a width of 853.3 pixels -- not allowed because of the odd number, but not horizontally divisible by 2, 4, 8, or 16. If you look at the standard sizes for all of SD and HD video, the dimensions are all mod-16 (except for 1920x1080, where 1080 is only mod-8, not mod-16). So for practical use it's best to stick with mod-8 at least. This means that to get a mod-8 width for a 480-pixel height, the width is rounded to 856. However, the clincher is that the crop is a compromise (I asked myself why the top is cropped?). The result at 856x480 square-pixel is actually about right, but only if you crop that extra 6 pixels off the top. Since we have no view of the original video frames, I'd have to say that the final image size is correct for 16:9 but with a little of the original top missing. |
The video had black borders all the way around, including a 6-pixel tall black region at the top and bottom. No head switching noise though, I don't think this source saw analog tape anywhere along the way to DVD. Promo Only gets their files directly from record labels (although in 2003 I don't know what format the labels would have been providing... probably MPEG-2, unfortunately, which means this underwent 2 lossy encodes in order for PO to add their stupid text overlay prior to DVD authoring). It's intended to be a 4:3 aspect ratio video. I think the 720x480 is due to overscan padding and DVD's not having a square pixel aspect ratio? PAR always confused me a little bit...
The screenshot I posted is a sloppy crop of hitting "print screen" on my keyboard, so no info to be gleaned from its dimensions. When I get home tonight I'll try your suggestions (cropping AFTER deinterlacing) and I'll skip creating fake 4:3 720p by upscaling. However, what's the best way to achieve a standard, square pixel 640x480 image from the 692x468 image that I'll end up with after cropping the original 720x480? Should I just spline64resize(640,480)? Would I be significantly better off quality-wise by living with the 6 black pixels top and bottom and limiting the resize to act horizontally 692 --> 640? |
With only 6 pixels at top and bottom each, this original video might be 1.6:1 movie film instead of 16:9, common in many circles. Certainly the original image wouldn't be "regulation" 1.85:1 movie or you'd have more pixels letterboxed top and bottom. I'd crop the side borders and make it 640x480 with the 6 pixels retained top and bottom. Trying to get the original 1.6:1 to fill the screen won't be possible, as it's neither 4:3 nor 16:9 image content. A capture of an entire frame with all borders would tell us more.
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Great news -- cropping AFTER TIVTC 100% fixed the color artifacts.
Also, thanks for your input on the other stuff! |
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