A short example though not pronounced on youtube - watch the guy in white shirt moving towards the camera:
http://www.youtube.com/watch?v=dQvgB1rg0HY
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Youtube doesn't help diagnose much, because it's progressive and re-encodes everything
So a 60i file would become 30p (you lose 1/2 the motion samples, so everything in motion will look juddery). Even if you uploaded original file, youtube will re-encode to 30p, so it doesn't indicate anything one way or another
A normal 60i file like your original video, when displayed properly will be bob deinterlaced to 60p (you will see 60 motion samples per second on your TV), that's why everything appears smoother
The question is at what stage are the errors occuring ? Uploading actual samples as requested earlier would quickly determine this
(or since you are in the UK, PAL 50Hz land, 50i would become 25p instead of 50p) -
Most of the interlaced videos I've seen uploaded to Youtube get blend deinterlaced by Youtube. It's odd that akkers' video show no blending artifacts. That makes me think the video was deinterlaced before being uploaded to Youtube.
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Correctly for what?
As has been mentioned a few times now, nobody can say exactly what is going wrong until you provide some un-reencoded samples. But the Youtube video was definitely converted to 30p and that is responsible for the flickery motion. See the video in this post:
https://forum.videohelp.com/threads/307004-Best-framerate-conversion-%28eg-23-97-to-30-...=1#post1888926 -
ok I will upload some un-encoded footage tomorrow. How do I 'cut' a small piece fdrom a long clip without re-encoding? Is there a good place to upload the files?
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So is that whats causing the judder in the end video? How to get round this?
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I wouldn't call that "judder". You are seeing two fields at once that were shot with 1/50th sec time offset hence you see double vision during fast motion.
Go back to source and use bob or "interpolate" deinterlace or if this is intended for DVD or Blu-Ray, just keep it interlace.
I usually edit camcorder video interlace to the edit master, DVD or Blu-Ray. If I need to deinterlcace for streaming, I do that off the edit master as a second path.Last edited by edDV; 3rd Dec 2011 at 15:55.
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The AVI sample he uploaded is interlaced, and fields are intact. It should have .m2t or .m2ts extension, because it's essentially HDV, either he renamed the extension or some other program did
If that is what is being loaded into vdub/deshaker, the input is ok, but he hasn't provided a sample of the export file -
Last edited by edDV; 3rd Dec 2011 at 17:08.
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The video at youtube was not blend deinterlaced. One field was discarded and the remaining field resized.
Attached is a version after deshaking and reencoding to MPEG 2 VBR with HcEnc. I didn't bother with making it pretty (wandering black borders).Last edited by jagabo; 3rd Dec 2011 at 17:49.
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I don't think youtube did anything to it. I think it just treated it as 29.97p, so adjacent fields are smashed together and treated as a frame
The low bitrate and compression make it appear if a field resize was done, but you can see fine combing from consecutive fields on individual frames
This is from the youtbe 1080p version (of course you have to view at full size): -
I only downloaded the 1080p version. It had no comb or blending artifacts when motions were large. But there is a bit when motions are small, like in your picture. That tells me it went through a smart deinterlacer like Yadif.
A frame from the youtube video with a lot of motion:
The same frame from the original video with blend deinterlace in VirtualDub (not resized for AR):
Last edited by jagabo; 3rd Dec 2011 at 18:06.
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I think it's bitrate related. In high motion, the quantizer is too high to preserve the fine pattern. As a result, what you see is a blending of edges. If youtube allocated a higher bitrate, I bet you would see cleaner separation and the same pattern in the screenshot during higher motion areas
EDIT: I'm going to take that back. jagabo I think your smart deinterlacer conclusion is correct. Unless youtube's encoder is really really poor, I cannot replicate the results using very poor settings at similar or even lower bitrates
But back to the main point : youtube cannot be used to diagnose where problems are occurringLast edited by poisondeathray; 3rd Dec 2011 at 18:58.
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The Youtube does not show the pronounced effect that I am seeing on tv. I think it is a kind of red herring.
The above video I attached plays sort of ok on tv. Its only when I put it through PP and output as avch or mpeg2 that I see judder (eg: peoples' hands shaking as they move).
I was going to post taht clip but there is a filesize limit here. -
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or you can use another free file hosting service if the cut segment is still too large
e.g. mediafire.com, sendspace.com, megaupload.com etc... -
Here is thew funny thing: I loaded the first full file into AP4 in a HDV 1440 project. Did a few edits and exported it as mpeg2 1440x1080 25i full quality file. THis came out ok - brilliant. I then loaded file 2 (recorded in the same camera and on the same day) - exported this with the exactly the same settings to mpeg2.
Now file1 exported footage is ok all the way. Exported file2 sets off ok and then degrades after a few minutes (juddering with motion scenes).
What puzzles me is that I could not for the life of me export file1 correctly - it always came out juddering. But today it came out ok. And then file2 starst off ok but deteriorates after a few mins.
This is driving me nuts! -
What were the differences between the sessions? Are you sure the sequence settings , and export settings were the same ?
Maybe something is wrong with file2 ? Does it play ok before your edits ? -
Premiere cannot export same HDV as original, videos will be recompressed again I'm afraid , seems like whatever you do problem is Premiere export, so,......., why not to try Debug Mode Frame Server and to serve uncompressed video to VirtualDub from Premiere's timeline.
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The juddering is not present in the original File2.
In fact File1 was the one which had the above clip (guy with white shirt). For days I vcould not get that file to export correctly and today, out of teh blue its worked. But when I did File2 immediately with the same settings I got the juddering problem again. -
It's might be as simple as you dialed in the wrong settings. For example , that AVI you posted should NOT be in an AVI container. Probably a simple mistake or button you pushed somewhere . Can't help you if you cannot be more specific or clear about what steps you are taking
_Al_ has a good suggestion, by frameserving into vdub for deshaker , you eliminated need for large intermediate files. -
No when I exported File1 and File2 they were exported with exactly the same settings.
I was hoping to post a small cut of file2 but it contains private material.
I know its silly but could the speed and performance of the hard disc have anything to do with this since I am getting inconsistent results. -
I have given up on this, I am afriad. I have asked the source to provide me the footage in another format.
I will come back to this later and try to unravel the mystery. -
The original source is from a HDV cam and should have top field first. The footage is actually reporting top field first as well. But I wonder if the capture was wrong and at some stage the field order has been switched.
I also notice that when I play through WMP the original (well, a small cutout) of the mpeg2 clip, there is massive 'combing' when there is movement.
If I play any other interlaced footage through windows media player, there is no combing effect but this footage produces massive amount of combing with moving scenes.Last edited by akkers; 10th Dec 2011 at 08:04.
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Once again, until you upload a sample of the converted video nobody will be able to tell you what's wrong. You should also upload samples from each intermediate step so we can determine where it happened.
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