Long GOP Artifacts

[johnmeyer]

Fog is a problem for long GOP compression. I'm trying to salvage some spectacular footage taken at 2:00 a.m. under the midnight sun by a DJI Inspire drone in the park on the north side of Iceland. Here is a sample from the original 4K footage, cut with ffmpeg:

DJI Inspire Drone Video Long GOP Jerkiness.MOV (https://www.mediafire.com/?giza4avndnrs4e5)

As you will see, the car's motion is smooth, but amorphous objects like the dark ground and the fog are "pulsing." I'm pretty sure this is caused by the inability of the interframe compression algorithm to track the featureless fog, and therefore the pixels associated with that "object" drift aimlessly during for seven frames, and then get harshly moved when an I frame happens every 8 frames. The car and the mountains in the background are perfectly smooth.

My goal is to reduce this harshness. One idea is to either sense (don't know how to do this) or at least mark the start of each GOP (I can afford to take the time to do this, if needed), and then replace the frames on either side with some sort of motion-estimate version. This won't fix everything, but it might reduce the impact of having the position of the fog moved all at once.

For those of you who look at this, you might want to brighten it a bit (increase the top half of the histogram). When brighter, the artifacts really pop out. Also, I have no problem fixing the sensor noise in the shadows, adjusting the gamma, and adding some "punch." It is only the GOP issue that I'm trying to solve.

Any other ideas or thoughts on how to approach this would be welcome.

[MWilson]

Quick testing showed that this helped on a 720x480 version of your video. (My netbook won't run 4k :( ) You may have to modify it a bit.

v=AVISource("F:\Drone OV.avi").converttoyv12()

v.autolevels(12)
a=last


b=a.gaussresize(width(v)/8,height(v)/8).gblur(2).gaussresize(width(a),height(a))

y1=overlay(a,b,mode="subtract")
y2=b.interframe("Faster","Smooth",60000,1001,cores=1).selectevery(4,0,3).temporalsoften(10,25,25,0).gblur(2)
y3=merge(y1.temporalsoften(8,25,25,0),y1,.25)
merge(y2,y3)
temporalsoften(10,20,20,0)
y4=last
return y4.f3kdb()

Here's the (new) result:https://drive.google.com/open?id=0B72PmD8lKDzSVUpCOE45YjlxaXc

Edit: Link Updated
Edit: Should allow more detail through.
Edit: Added link to new video.

[johnmeyer]

I looked at the video you sent to me before I looked at the script and I guessed that MVTools2 (via Interframe in this case) was involved. Let's see if I understand your approach:

I assume you converted to an AVI in order to deal with the container format of the original video.

The autolevels was to make it bright enough to see what's going on. It looks like you are doing some sort of subtraction of a blurred lower-res version of the video from the original video. I'm not sure what effect that produces and will have to try it out when I get back to my editing computer tomorrow.

After that it looks like you double the framerate and select the interpolated frames. You soften and blur those and then merge them with various softened versions of the original.

There is no doubt, from the sample you sent to me, that it does reduce the GOP artifacts but I won't know tomorrow how much violence has been done to the details. Despite the soft fuzzy nature of the video below the fog, there is still a lot of detail once the drone breaks through the fog and shows the mountains in the distance against the midnight sun. I don't want that to become too soft. However, if your technique works, I can mask your version with the original, letting the original video of the mountains show through the mask. I use Sony Vegas, and it is trivial to create a mask to let the mountains from the original video overlay your corrected version, and then keyframe that mask as the drone makes its ascent.

I think you're on the right track with this and I'll work with it tomorrow. Thanks!

I'm still very much open to other ideas and suggestions. This is actually a somewhat common problem that I've seen many times in other people's videos, so finding a good solution would benefit a lot of people other than just me.

[feisty2]

sorry for the late reply, just checked your sample and I think the problem is actually not the fog, it's the noise
see something like this?
http://i.imgur.com/68Dqil5.png
noise is dynamic in time dimension most of the time, and that makes it look less annoying in motion, and when you got large amount of noise in your vid, macroblocks will go random noise block alike, noise will be the dominate factor of SAD between 2 macroblocks and that messes motion estimation and compensation up, block matching works long as blocks are similar enough, and by "similar", that means the actual image, not noise, should be the dominate factor of SAD and SAD should be small, and in your case, block matching was screwed by noise, actually pretty similar situation like this, http://forum.doom9.org/showthread.php?t=173705

and now because me/mc was fucked, the noise in your compressed vid goes almost static in time dimension, and that's the cause of "jerkiness", trying to figure out a way to cure this...

[geometer]

B-frames in the dark already make some kind of freeze, especially in the noise. Because "lazy". It's a target issue in the evolution of MPEG. Old Divx4 was notorious. Later improved.

Masking, and to make data update even more lazy, might mitigate the issue. Within the dark-mask, a temporal smoother might almost cancel the new data from the i-frame. After done that, reverse processing might carry the remainder of the i-frame data into the earlier frames also. Means actual bidirectional temp-smooth. Needs then a threshold to stop that and update much faster (maybe adjust during ~4 frames while otherwise might be quite lazy during a whole second), when something relevant blends in within the dark area.

[feisty2]

@johnmeyer
the processed sample here,
https://mega.nz/#!jx8TUAhB!VfsoBw2LR70K6QHq8K92NQeqgeUPZ0Fls1IH4RjICYY
random stuff:
1. scaled to 1920x1080 cuz block matching at 4k is way too heavy to my crappy i7-4790k
2. ditched chroma planes, I simply don't care much about chroma and the artifacts show mostly on luma plane anyways.
3. losslessly compressed with avc lossless

Does it look okay to you now?
the solution is a bit complex, so, I'm waiting for your reply.
I'll go on explaining if the answer is "yeah"

[StainlessS]

One idea is to either sense (don't know how to do this) or at least mark the start of each GOP

Perhaps of use

Loadplugin("ffms2.dll")
Import("ffms2.avsi")

SSS="""
Global Glb_FrameType = FFPICT_TYPE # Maybe you want it somewhere else
RT_DBaseSet(DB,current_frame,Glb_FrameType)
RT_Subtitle("%d] %c",current_frame,Glb_FrameType)
return last
"""

FN="big_buck_bunny_720p_h264.mov"
FFmpegSource2(FN)

DB = "Meyer.DB"
RT_DbaseAlloc(DB,Framecount,"i") # FrameCount Records, Single field of type int, CAPS character code ie 'I'=73, 'P'=80, 'B'=66.

ScriptClip(SSS,after_frame=true)


EDIT: You can remove the DBase stuff if all you want is the Global, but using DB allows presetting of all DBase fields,
and then real run with access to current GOP start, previous and next GOP (via backward/forward scan of DB).

EDIT: By using another global and 2 additional int fields, could track previous I frame, and set 2nd field (field 1) to eg previous I frame,
and then set previous I frame's (field 2) next I frame to current frame (if that makes sense), in real run, allow access to prev and next I frame
numbers without scan backwards/forwards.

[feisty2]

Quick testing showed that this helped on a 720x480 version of your video. (My netbook won't run 4k :( ) You may have to modify it a bit.

v=AVISource("F:\Drone OV.avi").converttoyv12()

v.autolevels(12)
a=last.interframe("Faster","Smooth",60000,1001,cores=1).selectevery(4,0,3)


b=a.gaussresize(width(v)/12,height(v)/12).gblur(2).gaussresize(width(a),height(a))

y1=overlay(a,b,mode="subtract")
y2=b.interframe("Faster","Smooth",60000,1001,cores=1).selectevery(4,0,3).temporalsoften(10,25,25,0).gblur(2)
y3=merge(y1.temporalsoften(8,25,25,0),y1,.25)
merge(y2,y3)
temporalsoften(10,20,20,0)
y4=last
y5=merge(a,y4,.9)
return y5.f3kdb()

Here's the result:https://drive.google.com/open?id=0B72PmD8lKDzSZ2p0SXpkdTFIVFE

Edit: Should allow more detail through.
Edit: Added link to video.

I'm just gonna be blunt here, your solution sucks
the fog looks kind of normal and the auto and the mountain are shimmering like hell, cuz you merged interpolated frames with the source frame, and that's toxic, like that lame and dumb "ConvertFPS" trick, motion interpolation is far from perfect first, and just say if it was indeed perfect, you're merging frames at different time coordinates together, and that = ghosting + shimmering and other shit like that

I didn't use no motion interpolation, you see the problem is NOT low framerate so motion interpolation is so not the solution

[MWilson]

Feisty,

Just return y4. FWIW, I like your solution. But belittling other folks' is flat out mean. Constructive criticism is one thing, but when you are trying to help someone, you don't expect hostility.

Good Luck.

[poisondeathray]

feisty, I'm interested in your approach (but it's not fun running your typical scripts which eat too much memory and run at 0.0001 FPS :D )

The motion is better, but is there a way to preserve the ground detail, and to work with CbCr ? Especially the ground rocks near the jeep, and they are present in the Y' channel, but filtered out in your video. I suppose masking/overlay is one option bring it back

[feisty2]

Feisty,

Just return y4. FWIW, I like your solution. But belittling other folks' is flat out mean. Constructive criticism is one thing, but when you are trying to help someone, you don't expect hostility.

Good Luck.

fine, I didn't mean to be mean but I always forget the difference between "blunt" and "mean" is fragile..
you were trying to be blunt and ended up being mean

sorry then

[feisty2]

(but it's not fun running your typical scripts which eat too much memory and run at 0.0001 FPS )


if you got the access to a supercomputer or whatever..

is there a way to preserve the ground detail

maybe... guess the sigmoidal light might work for this
and to work with CbCr ?
simple, remove "clp = core.std.ShufflePlanes(clp,0,vs.GRAY)"

[StainlessS]

One idea is to either sense (don't know how to do this) or at least mark the start of each GOP

Further to above:

Script to Create DBase where for each record(frame) there are 3 int fields, 0) frame status, 1) frameNo of prev I frame, 2) frameNo of Next I frame.

# https://forum.doom9.org/showthread.php?p=1775535#post1775535

Function DB_Write(string DB,int n,int type) {
RT_DBaseSet(DB,n,Type,Glb_PrevIFrame,-1)
GSCript("""
if(Type==73) { # I frame
if(Glb_PrevIFrame>=0) {
for(i=Glb_PrevIFrame,n-1) {
RT_DBaseSetField(DB,i,2,n) # Set all previous GOP frames 'Next I frame field' to current frame n
}
}
Global Glb_PrevIFrame=n # Remember current frame as previous I frame when at following frames
}
""")
return 0
}

#Loadplugin("ffms2.dll")
Import("ffms2.avsi") # May need path if not in current directory

FN="K:\TESTAVI\big_buck_bunny_720p_h264.mov"
FFmpegSource2(FN)

DB = "Meyer.DB"
DB=RT_GetFullPathName(DB)

SHOW =True
FORCE=true # Use ForceProcessAVI
Global Glb_PrevIFrame = -1 # Unset
RT_DbaseAlloc(DB,Framecount,"iii") # FrameCount Records, 3 fields of type int,
# Field 0) CAPS character code of current frame(record), ie 'I'=73, 'P'=80, 'B'=66.
# Field 1) frame number(record) of previous I frame
# Field 2) frame number(record) of next I frame

SSS="""
FrameType = FFPICT_TYPE # Have to use FFPICT_TYPE from main level script, not global.
(Show&&!FORCE) ? RT_Subtitle("%d] %c Prev=%d ",current_frame,FrameType,Glb_PrevIFrame) : NOP
DB_Write(DB,current_frame,FrameType) # function as we want GScript
return last
"""

ScriptClip(SSS,after_frame=true)

(FORCE)?ForceProcessAVI():NOP # From TWriteAVI, Fast creation of DBase (or RT_ForceProcess from RT_ v2.0)

Return Last



And DBase Viewer/Checker

#Loadplugin("ffms2.dll")
Import("ffms2.avsi") # May need path if not in current directory

FN="K:\TESTAVI\big_buck_bunny_720p_h264.mov"
FFmpegSource2(FN)

DB="Meyer.DB"
DB=RT_GetFullPathName(DB)

SSS="""
n=current_frame
typ=RT_DBaseGetField(DB,n,0)
prv=RT_DBaseGetField(DB,n,1)
nxt=RT_DBaseGetField(DB,n,2)
RT_Subtitle("%d] %c PrevI=%d NextI=%d",n,typ,prv,nxt)
return last
"""

ScriptClip(SSS)
return last


I have not as yet downloaded your clip, so I used a mov that I do have.

EDIT: Req, RT_ Gscript (and TwriteAVI v2.0 if required).

[johnmeyer]

@johnmeyer
the processed sample here,
https://mega.nz/#!jx8TUAhB!VfsoBw2LR70K6QHq8K92NQeqgeUPZ0Fls1IH4RjICYY
random stuff:
1. scaled to 1920x1080 cuz block matching at 4k is way too heavy to my crappy i7-4790k
2. ditched chroma planes, I simply don't care much about chroma and the artifacts show mostly on luma plane anyways.
3. losslessly compressed with avc lossless

Does it look okay to you now?
the solution is a bit complex, so, I'm waiting for your reply.
I'll go on explaining if the answer is "yeah"The answer is definitely "yeah." Your approach does seem to have pretty much nailed the pulsing.

However, I feel like Spock in the original Star Trek "Operation -- Annihilate!" episode when McCoy tries to free him from the pain of a parasite. After the procedure Spock says: "I'm also quite blind. An equitable trade, Doctor. Thank you."

So in this case, the pain of the pulsing is gone, but I'm now color blind because the video no longer has any color.

Did you ditch the color planes in order to make it work, or did it simply help speed up the fix? I would obviously like to keep the color since that is part of the "payoff" when the drone breaks through the fog. However, if that is not possible, I actually might be able to create something this is visually even more dramatic, with the fog and below done in B&W, and then I mask in the original footage of the mountains. As I indicated earlier, that is a trivial operation with the NLE I use.

I'm obviously very interested in the script you used and hope I can adapt it to my computer and setup. Thank you very much for doing this.

[feisty2]

The answer is definitely "yeah." Your approach does seem to have pretty much nailed the pulsing.

However, I feel like Spock in the original Star Trek "Operation -- Annihilate!" episode when McCoy tries to free him from the pain of a parasite. After the procedure Spock says: "I'm also quite blind. An equitable trade, Doctor. Thank you."

So in this case, the pain of the pulsing is gone, but I'm now color blind because the video no longer has any color.

Did you ditch the color planes in order to make it work, or did it simply help speed up the fix? I would obviously like to keep the color since that is part of the "payoff" when the drone breaks through the fog. However, if that is not possible, I actually might be able to create something this is visually even more dramatic, with the fog and below done in B&W, and then I mask in the original footage of the mountains. As I indicated earlier, that is a trivial operation with the NLE I use.

I'm obviously very interested in the script you used and hope I can adapt it to my computer and setup. Thank you very much for doing this.

relax, it works on chroma as well, I disabled chroma processing cuz I do my algorithm designing stuff on Y and extend that to UV or RGB once I finished the designing like always..
kind of a personal habit

[feisty2]

import vapoursynth as vs
import mvmulti
import Vine
import Oyster
core = vs.get_core()

clp = core.lsmas.LWLibavSource("DJI Inspire Drone Video Long GOP Jerkiness .MOV")
clp = core.fmtc.bitdepth(clp,bits=32,fulls=False,fulld=True) #convert to floating point precision and full range
clp = core.std.ShufflePlanes(clp,0,vs.GRAY) #extract Y
clp = core.fmtc.resample(clp,1920,1080,kernel="cubic",a1=-1,a2=0) #scale to 2k
clp = core.fmtc.transfer(clp,"709","470bg",fulls=True,fulld=True) #brighten it up, dont want dark details all fucked up

pre = Vine.helpers.padding(clp,17,17,17,17) #pad, in spatial dimensions
pre = core.std.Reverse(pre)+pre+core.std.Reverse(pre) #pad, in temporal dimension
pre = core.knlm.KNLMeansCL(pre, 16, 8, 1, 6.4) #very large time radius NLMeans, motion flow and denoising 2 in 1, more of motion flow here
pre = core.std.Trim(pre,269,537) #remove padding in temporal dimension
pre = core.std.CropRel(pre,17,17,17,17) #remove padding in spatial dimensions

#"pre" looks super smooth in motion because of the motion flow alike NLMeans, and super washed out...

supv = core.mvsf.Super(pre) #blah
supd = core.mvsf.Super(core.std.MakeDiff(clp,pre)) #blah
vec = mvmulti.Analyze(supv,tr=16,blksize=32,overlap=16,search=3,badrange=-24) #blah
vec = mvmulti.Recalculate(supv,vec,tr=16,blksize=16,overlap=8,search=3) #blah
vec = mvmulti.Recalculate(supv,vec,tr=16,blksize=8,overlap=4,search=3) #blah
vec = mvmulti.Recalculate(supv,vec,tr=16,blksize=4,overlap=2,search=3) #blah
dif = mvmulti.DegrainN(core.std.Expr(clp,"0.5"), supd, vec, tr=16,thsad=10000,thscd1=10000,thscd2=255) #stabilize the difference between clp and pre
clp = core.std.MergeDiff(pre,dif) #merge the difference back

#no more washed out now

supr = core.mvsf.Super(clp) #blah
bv = core.mvsf.Analyze(supv,delta=3,blksize=32,overlap=16,search=3,badrange=-24,isb=True) #delta=3 is good, delta=1,2 ain't effective enough
fv = core.mvsf.Analyze(supv,delta=3,blksize=32,overlap=16,search=3,badrange=-24,isb=False) #blah
blr = core.mvsf.FlowBlur(clp, supr, bv, fv, 100,thscd1=10000,thscd2=255) #do a full time motion blur here and make the fog look smoother than ever
blr = Oyster.helpers.thr_merge(blr,clp,thr=8/256,elast=2/256) #don't want motion blur on the entire frame
#only want that on the fog, and fog is kind of the delicate and flat feature here
#this filters out motion blur on strong and significant features like the auto and moutains
clp = Vine.helpers.cutoff(blr,clp,8) #this filters out motion blur on high frequency features

clp = core.grain.Add(clp, 2) #some extra grain here to make it look less... whatever
clp = core.fmtc.transfer(clp,"470bg","709",fulls=True,fulld=True) #reverse the brightening

clp.set_output()

[feisty2]

If you can reduce the problem, you're a genius. I'll try to figure out how to upload enough without compromising the business negotiations. The people who own the video are trying to sell it to the car company whose vehicle is featured, and there is some real money involved. I'll start a new thread when I'm ready to do that. I want to see how far I can get by sensing the "jump" points and then using motion estimation to smooth out the video at those points.

I'm a genius obviously by that definition, and I wanna hear you say IT!
I'm so fucking depressed and mad cuz I got matrix mechanics class the entire day and I was goddamn exhausted and my boyfriend bitched about how I can't cook when I got back to my apartment.

really really could use some praising right fucking now

[johnmeyer]

Digesting this ...

It doesn't look like translating this into an AVISynth script is doable. Vapoursynth is a big hill to climb for this old fart ... need to figure out how many things to download, and which computer I need to use ...

I'll post again after I've done a little homework.

[Reel.Deel]

I'm a genius obviously by that definition, and I wanna hear you say IT!
I'm so fucking depressed and mad cuz I got matrix mechanics class the entire day and I was goddamn exhausted and my boyfriend bitched about how I can't cook when I got back to my apartment.

really really could use some praising right fucking now

Somethings are better left unsaid...

Digesting this ...

It doesn't look like translating this into an AVISynth script is doable.

Looking at feisty's script this should be doable in AviSynth. Not too long ago I had some HFR video and there where parts of the video that was flickering (and pulsating a bit) due to artificial lighting. I tinkered a bit but never came up with anything solid, might have to play around with it some more.

[feisty2]

Looking at feisty's script this should be doable in AviSynth.
No it's not, you got no Expr in avisynth and that makes the_merge impossible to port, and lut is useless because the precision is way too low, you need as much precision as you can under "470bg" light

Somethings are better left unsaid...

I'm not that kind to help johnmeyer for nothing, and obviously I'm not getting paid, so it's for my ego, John said that would make me a genius!

Fine, I was kidding... I just want some comfort from a stranger online, feels kind of pathetic now..

[MWilson]

I'm not that kind to help johnmeyer for nothing, and obviously I'm not getting paid, so it's for my ego, John said that would make me a genius!

Fine, I was kidding... I just want some comfort from a stranger online, feels kind of pathetic now..

Vapoursynth or avisynth, that's excellent work.

[poisondeathray]

Before I try it and blow up a computer, :D what FPS and memory consumption are we talking about for "only" 1080p ? I know from past experience to ask. Your scripts should have a disclaimer

But thanks for putting the little #comments so I can eventually follow along

[feisty2]

Vapoursynth or avisynth, that's excellent work.

you're a nice one, thx!

Before I try it and blow up a computer, :D what FPS and memory consumption are we talking about for "only" 1080p ? I know from past experience to ask. Your scripts should have a disclaimer

But thanks for putting the little #comments so I can eventually follow along
split the script and the performance will be acceptable


import vapoursynth as vs
import Vine
core = vs.get_core()

clp = core.lsmas.LWLibavSource("DJI Inspire Drone Video Long GOP Jerkiness .MOV")
clp = core.fmtc.bitdepth(clp,bits=32,fulls=False,fulld=True)
clp = core.std.ShufflePlanes(clp,0,vs.GRAY)
clp = core.fmtc.resample(clp,1920,1080,kernel="cubic",a1=-1,a2=0)
clp = core.fmtc.transfer(clp,"709","470bg",fulls=True,fulld=True)

pre = Vine.helpers.padding(clp,17,17,17,17)
pre = core.std.Reverse(pre)+pre+core.std.Reverse(pre)
pre = core.knlm.KNLMeansCL(pre, 16, 8, 1, 6.4)
pre = core.std.Trim(pre,269,537)
pre = core.std.CropRel(pre,17,17,17,17)
pre.set_output()


vspipe xxx.vpy pre.rgb -p



import vapoursynth as vs
import mvmulti
core = vs.get_core()

clp = core.lsmas.LWLibavSource("DJI Inspire Drone Video Long GOP Jerkiness .MOV")
clp = core.fmtc.bitdepth(clp,bits=32,fulls=False,fulld=True)
clp = core.std.ShufflePlanes(clp,0,vs.GRAY)
clp = core.fmtc.resample(clp,1920,1080,kernel="cubic",a1=-1,a2=0)
clp = core.fmtc.transfer(clp,"709","470bg",fulls=True,fulld=True)

pre = core.raws.Source("pre.rgb",1920,1080,src_fmt="GRAYS")

supv = core.mvsf.Super(pre)
supd = core.mvsf.Super(core.std.MakeDiff(clp,pre))
vec = mvmulti.Analyze(supv,tr=16,blksize=32,overlap=16,search=3,badrange=-24)
vec = mvmulti.Recalculate(supv,vec,tr=16,blksize=16,overlap=8,search=3)
....

[johnmeyer]

I spent some time looking at what is involved in learning Vapoursynth, Python, etc., and downloading all the plugins. At my advancing age (Medicare is less than ten months away), the old question "can you teach an old dog new tricks?" has been answered, and unfortunately that answer is: no. It is way more involved than AVISynth.

So, despite the amazing results with the Vapoursynth script, I am back trying to fix this using tools I have somewhat mastered. I tried what StainlessS suggested, but rather than wrestle with automatically marking the discontinuity points, I instead simply created a duplicate at each point (I have a script in Vegas that lets me do this easily), and then used FillDrops() to replace the dup with a motion estimated frame.

I then played around with various denoisers. I spent quite a bit of time looking at Feisty's script, and his comments in the script about filtering based on spatial frequencies made me think of the old fft3DFilter that I haven't used for awhile. I've been using various sigma settings and have started to get something that is a little better than the original, although not yet in the same league with Feisty's results.

I'll keep plugging away at it for the next few days. If anyone has other hints or suggestions, let me know.

And, thanks again to Feisty. I'm truly sorry I can't figure out how to use your script.

[feisty2]

I spent some time looking at what is involved in learning Vapoursynth, Python, etc., and downloading all the plugins. At my advancing age (Medicare is less than ten months away), the old question "can you teach an old dog new tricks?" has been answered, and unfortunately that answer is: no. It is way more involved than AVISynth.

there's really no big difference between avisynth scripts and vaporsynth(python) scripts I think..
both are "scripts" which is the programming language term for "super simple stuff", you get one, you'll handle the other one within half an hour reading the doc
I just think they simply cannot get any simpler, you'll know how simple vaporsynth scripts are if you ever tried to implement your idea with a C/C++ plugin instead of a script, most of the time it's like "how and why the fuck does it crash unexpectedly??!!" or worse, "why the fuck does the output look corrupted???", then you go debugging for like an hour or hours to trace the error and found out you forgot to move some pointer to the next line or something like that.. It's no longer about the algorithm and your idea and stuff, it's all about programming, and that definitely sucks for real
and age really doesn't matter, vcmohan is 80+ years old, approximately the same age as my grandpa, and he wrote quite a few vaporsynth plugins! RESPECT to him.