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14th October 2014, 21:37 | #1 | Link |
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Flicker/Pulsate Problem with QTGMC
I really like QTGMC but anything I use it on I notice that static areas in the picture move and are all warbly/flicker/pulsating.
You can see what I'm talking about in this clip here: http://www.mediafire.com/download/49...61k/DEMI+3.mpg Here is script I used on that clip: QTGMC() SelectEven() And you will see the problem I am describing, most noticeable in the upper left hand corner (the walls flicker/pulsate). Anyway to tweak QTGMC so it doesn't do this? Or is there something else I'm missing? Thanks and any help would be very much appreciated. J |
15th October 2014, 00:10 | #5 | Link |
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Why are you processing this clip with QTGMC? What was the problem in the original clip that you were attempting to fix?
I ask this because the main function QTGMC provides is deinterlacing, and since your clip is from a PAL film source, I would expect that no deinterlacing is required. Thus, you may have created the problem by using the wrong tool (QTGMC) for the job. |
15th October 2014, 07:56 | #6 | Link | |
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I am using QTGMC because even though the source is a PAL DVD, it's phase-shifted and full of interlacing. The company that produced the DVD didn't know what they were doing. It can be fixed with: TFM() but.....it leaves aliasing. That is why I like QTGMC because it smooths away the aliasing. QTGMC is doing it's job great by fixing the interlacing issues but I'm trying to figure out why it's causing the "flickering/pulsating" problem. That is my question. Thanks, J |
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15th October 2014, 14:06 | #7 | Link | |
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However, since you don't appreciate my attempt to help you, there is no point in my providing any further assistance. [edit]I just walked through the entire clip, one more time, field-by-field. There is no interlacing or phase shifting. Therefore, either this clip has already been processed or, if it is the original clip as you claim, there is no problem. Last edited by johnmeyer; 15th October 2014 at 14:16. |
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15th October 2014, 18:39 | #8 | Link |
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johnmeyer: Get your head out of your ass. If you don't want to be insulted, stop being wrong.
The sample the OP posted does in fact have wrong phase and severe combing/aliasing artifacts. Yes, ideally, the OP should've posted the source with absolutely no processing or reencoding. But an unfiltered reencode would be good enough to diagnose source issues, too.
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15th October 2014, 18:47 | #10 | Link |
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You're quite welcome, if you're going to be all passive-aggressive at being called out for being wrong. (This isn't even the first time I've done that either!)
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16th October 2014, 04:05 | #12 | Link | |
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For the record, if you re-read all the posts above, you will see that it was not I who made the comment about TMPGEnc. Must be a full moon tonight ... |
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16th October 2014, 04:26 | #13 | Link |
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Yes, john, we know you're a software engineer. And this is related to video in....what way did you say?
The video sample has a field shift and field phase problem at about frame 30. The sample is interlaced. TMPGenc smart rendering encodes only a few starting and ending fields in a GOP. You can see the smart rendering in the two starting and two ending GOP's, which are nominally GOPs of 15 frames. The other, un-rendered GOP's are ridiculous 5-frame GOPs with a different field priority. If you want completely unrendered frames from smart rendering editors, start a cut only on key frames. And don't tell your app that the video is TFF when it's really BFF, and vice versa. Another way to get same-as samples is to cut an m2v video file with the DGindex utility. What's the story on this video? Where did it come from? Recorded off cable TV? I have 3 MPG recordings of this Lawrence Olivier movie and a DVD issue, but after just now looking at two of my cable recordings I see hard-telecined NTSC MPEG with 15-frame GOP's. I don't have a PAL version. Maybe try DGIndex to make a cut to avoid any disputes. Last edited by LemMotlow; 16th October 2014 at 04:45. |
16th October 2014, 07:06 | #14 | Link | |||
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Might look a little better if you run a deflicker and stabilizer. This is what I used: Code:
LoadVirtualDubPlugin("Drive:\path\VirtualDub\plugins\Deflick.vdf", "DeFlick",1) QTGMC(preset="very fast").SelectEven() Stab() ConvertToRGB32(matrix="Rec601",interlaced=false) DeFlick(0, 8, 0, 0, 0) ConvertToYV12(interlaced=false) ReplaceFramesMC(301,1) aWarpSharp2(depth=5) AddGrainC(1.0,1.0) Crop(2,2,-10,0).AddBorders(0,2,12,0) grayscale() return last https://www.mediafire.com/?6d7q8a6vhb4vl0d With bad source there are things you can fix, and things you can't. Last edited by LemMotlow; 16th October 2014 at 07:10. |
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16th October 2014, 11:54 | #15 | Link |
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1) Ignore the field order transition that DGIndex wants to fix. The clip is 100% TFF.
2) It's field shifted. 3) After pairing the fields that belong together there's residual combing and aliasing left. So my suggestion is: Code:
DoubleWeave().SelectOdd() QTGMC(InputType=2) Personally I would also make use of QTGMC's Noise Bypassing because the clip looks kinda artificial to me without the noise. Code:
QTGMC(InputType=2, NoiseProcess=2, GrainRestore=1, NoiseRestore=0.5, NoiseTR=2) Last edited by TheSkiller; 16th October 2014 at 12:02. |
16th October 2014, 19:40 | #18 | Link |
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I have some interesting findings to report.
I went back and looked at the clip again, but using a different software tool than what I usually use, and I can see why some of you think I have my head in a dark place. The problem around frame 30 is massive and obvious. However ... I went back and looked at the clip again using my normal software, which is what I used in my initial tests, and the clip played just fine, without any issues whatsoever at frame 30, or elsewhere. So, when I posted above, I wasn't seeing any of the major problems that other people are seeing. I've had this happen before with some MPEG-2 files, but I'm not sure what causes the problem. There is still a major issue with warping of the odd fields. If you do a separatefields() or bob() and then look at each field, you will see a huge amount of shift between the even and odd fields, but only in the upper right and upper left corners. In the middle of the frame, there is almost no shift at all (i.e., a normal amount of bob). In other words, the odd fields are warped (the way I count, the first field is odd). I would guess that this is what leads to the flicker that the OP reported. I will leave it to others to speculate how only the odd fields got warped, whereas the even fields appear to be linear (i.e., horizontal straight lines are still horizontal and straight). Perhaps some sort of resizing issue in the chain of events which led to this video. To show you what I am seeing, here is an animated GIF showing the two fields from one frame. I scaled these back to 4:3 to make it easier to view. Look at the center of the frame and note the up/down shift and compare it to what is going on in the upper-left and upper-right corners. As you can see, the movement in the corners is far more than just the bobbing due to the offset between scan lines. Odd/Even Field Showing Warp Every frame in the entire clip has this same problem. If I come up with some solutions, I'll report back. Last edited by johnmeyer; 16th October 2014 at 19:45. Reason: Added: Every frame in the entire clip has this same problem. |
16th October 2014, 23:46 | #19 | Link |
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Reel.Deel linked to a Didée script that seems to fix the problems that I showed in my animated GIF.
Thank you, Reel.Deel! The field phase shift issue didn't show up on my computer because I use a different workflow that I use to feed MPEG-2 files into my scripts (see my previous post). However, if you read Didée's post in the thread to which Reel.Deel linked, he explains how to deal with that. For this video, phase shift is not the difficult issue. So, I removed the field warp using Didée's script, and then took that result and fed it into my version of VideoFred's film restoration script, but with most of the parameters turned way down, and the motion stabilization turned off, and deflicker enabled. I've uploaded the result, but in PAL DV format, just to make sure we eliminate any MPEG-2 reading errors from the discussion. Here is the result: Fixed and Enhanced Last edited by johnmeyer; 16th October 2014 at 23:48. Reason: spelling error that I didn't catch |
2nd November 2014, 22:59 | #20 | Link | |
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I liked the results from this one the best much appreciated J |
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