I gave some edited footage to an expert to look over (as I was experiencing some problems) and he gave me this response:
"I had a look at your clip today and I noticed that it has an odd field pattern of mostly progressive 50 frames per second but sections of duplicated frames. Something like:
So I split it into fields and ran it through a script that detects duplicate frames. I've attached the first script. It shows frame numbers on the left followed by a number with 5 decimal digits, a value of around 2 indicates it is the same frame as the one before it. However this is not exact."
(I have attached the script to this post)
Now unfortunately he is totally unavailable to contact. I am hoping to pay someone else to fix the problem but won't be able to tell if they've fixed it without a broadcast monitor - which I don't own.
Can anyone tell me how to reproduce a test like this and how to read the results to find out if my video has an 'odd field pattern' or duplicate frames? Thanks!
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The best test is your eyes . Either look at the fields individually or "bob" them to frames
Scripts are not always reliable - false positives, false negatives. Compression "noise" can confound metrics and results (e.g. a true duplicate will be missed because of temporal compression differences)
Duplicate frames can be "normal" when you intermix sections for example like you did with 25p and interlaced. They can be normal even in interlaced content (e.g. when you have a static shot) .
You should know the drill by now...
Post an unprocessed sample that demonstrates the problem
Broadcast monitor is only as reliable as the setup - if it wasn't setup properly you might be getting incorrect results
Virtual Dub using Donald Graft's MultiDecimate filter in an AviSynth script:
Unfortunately, Donald Graft's site with all his filters seems to be gone now. I'll include it here in case you'd like to try. After creating that mfile.txt, you can then remove those duplicate frames. But, as pdr suggests you might not need MultiDecimate and might be able to remove the dupes with a more simple decimation filter (TDecimate). But a sample is needed to be sure.
The attachment didn't work in this post for some reason, see the post below.
Last edited by kieranvyas; 21st Aug 2015 at 18:15.
The editor I am thinking about hiring said: "I think the issue might be as simple as going back to the beginning and working in a different timeline."
Source footage is: 1920x1080 progressive 50fps MPEG-4 Quicktime
EDIT: I have just realised, the first half of 'worst(short)' is slowed down in premiere pro. The second half is the clip played normally. Hopefully that won't affect tests.
Last edited by kieranvyas; 22nd Aug 2015 at 05:52.
LanczosResize(750,576)#or whatever resizer you like
Then encode it as interlaced and 16:9. I have no idea how you did it yourself.
Your black levels seem okay, if a bit high. Your white levels are definitely high, blown out in places, even.
I thought this thread was about duplicate frames?
I decided to send my project to a professional company for encoding as my results were just rubbish, even after troubleshooting. That was the exact avisynth I am using but in places there were interlace lines through objects in motion and it looked awful. So this company replied to me saying my uncompressed edited file had an 'odd field pattern' and 'duplicated frames' which would explain any stuttering or interlace lines showing. They said that lots of work needed to be done before the encoding stage. If my source footage is fine, then I must be messing it up in PP somehow. If you could confirm this by testing some frames on the uncompressed edited file I posted previously I would be eternally grateful. Thank you!
Last edited by kieranvyas; 22nd Aug 2015 at 08:13.
Maybe you have the field order set wrong in your encoder? AviSynth assumes BFF by default so the output of the aforementioned script will be BFF.
ffVideoSource("TODD IN PEN FIRST TIME..mov") Spline36Resize(720,576) AssumeTFF() SeparateFields() SelectEvery(4,0,3) Weave()
Last edited by jagabo; 22nd Aug 2015 at 08:48.
AssumeTFF().SeparateFields().SelectEvery(4, 0, 3).Weave()
Hopefully manono can test the uncompressed file I posted to confirm this!
Last edited by kieranvyas; 22nd Aug 2015 at 08:45.
Yes, your AVI file in post #7 has many duplicate frames. That could cause comb artifacts (after conversion to interlaced MPEG 2) upon playback as the player might get confused about whether the video is progressive or interlaced. It will definitely cause jerky playback. I added an HCEnc encoded video to my last post.
By the way, that file isn't uncompressed, it's losslessly compressed with Lagarith.
Last edited by kieranvyas; 22nd Aug 2015 at 11:03.
VirtualDub and stepped through frame by frame. It had duplicate with a pattern like 1 1 2 3 3 4 5 5 6 7 8 8. So about 3 duplicates in every 12 frames. Since it has the same 50 fps frame rate it runs longer.
You can do the same thing in premiere. Advance frame by frame and check for duplicates or missing frames
The MOV looks to be re-wrapped AVCHD (not prores) . There is no problem in premiere here on that MOV on the PC version CC2015. I noticed that your AVI said PP CC 2014 in the metadata - so you might consider upgrading to the newest version to see if it helps. Also clear out the cache files before you do any tests. But there are differences between the Mac and PC version of PP
Another thing you can try is actually converting it to prores before editing. It's a lot more stable and consistent to edit on Macs.
Last edited by kieranvyas; 22nd Aug 2015 at 11:55.
Yes, the second part of the AVI is fine
Upload a section of the final render, that exhibits the problem when viewed on a broadcast monitor. Describe exactly what the problem is - is it just horizontal lines or combing similar to seeing the video not deinterlaced on a flat panel? Or is it something else ?
Also if you know how it was setup, connections - e.g what was connected to what, HD-SDI to what, how was it played etc...
Here is some footage (11secs) of the worst parts.
worst3.1 = lossless export from PP (1st half)
worst3.2 = lossless export from PP (2nd half)
worst3 = final encode
This footage is comprised of 3 clips. Apologies for probably using the incorrect terminology but the symptoms are:
#1 the video is stuttering causing a motion blur around the dog, like it is ghosting
#2 lines over the dog during motion, distortion (the source footage of this clip is the one attached in a previous post above)
#3 large wavy lines/distortion on the bottom of the screen
I don't have access to a broadcast monitor at the moment unfortunately, so I am experiencing these problems on a flat panel TV and DVD player.
Avisynth script for worst3 (final encode):
AviSource("worst3.avi") ConvertToYV12() Spline36Resize(720,576) Blur(0,0.5) ColorMatrix(mode="Rec.709->Rec.601",clamp=0) AssumeTFF().SeparateFields().SelectEvery(4, 0, 3).Weave()
Last edited by kieranvyas; 22nd Aug 2015 at 18:00.
I don't see anything wrong with the interlacing in worst3.m2v. It has TFF interlaced frames, encoded interlaced TFF, 50 different fields per second. It should play back normally on any device that handles interlaced video properly. If you see interlaced comb artifacts on playback it's a shortcoming of the player's or TV's deinterlacing. Thin horizontal lines of the fencing will cause aliasing artifacts.
I think he's changed the problem description
I think this was discussed in your other thread - Those artifacts around the dog are compression artifacts mostly related to low bitrate. You can't encode high motion (difficult to compress scenes) with low bitrate MPEG2 and expect it to look ok. Those blocky artifacts around the dog may give the subjective impression of "ghosting" or "motion blur", because the separation between foreground object (dog) and background (grass) isn't as distinct. But I'm curious about the choice of words "stuttering". I don't see any evidence of that
I am planning on paying a professional company to encode the DVD, but they took my lossless sample and said 'it had an odd field pattern' but they may have been referring to the slow motion parts. If you could do me one last favour and check one of the lossless samples I attached in my previous post, and confirm there is nothing wrong with it, then I will know it is the encoding that is the problem and hopefully this company will fix that - as much as is possible.
lagarith AVI samples. There is no "field" pattern per se - because they are all progressive still at that point (50p)
Yes , there are duplicate frames in that one slow motion section you referred to. There are other options to generate slow motion "inbetween" frames besides frame duplicates - you can look into motion interpolation (aka "optical flow") options (e.g. twixtor, kronos, timewarp - or avisynth options like mvtools , mflowfps, svpflow) . But they have drawbacks such as edge morphing artifacts
Don't expect too much improvement from the encoding from a professional company. You simply can't get around that low bitrate MPEG2 limitation.
The only way to improve it (more than a little bit) is to use higher bitrate e.g. maybe use DVD9 . Other things you can do are structure the edit differently - intersperse more low motion scenes with high motion scenes. That way the buffer has more time to recover, you can distribute the bitrate more effectively. Also consider using DC10 and maybe a low bitrate matrix, softer resizing at least for the high motion scenes . You can also prefilter the high motion scenes with mild denoising which will reduce the compression requirements
Last edited by poisondeathray; 22nd Aug 2015 at 19:50.
It's actually not that difficult to check it yourself in the future - jagabo mentioned one way - just open the AVI into vdub and go frame by frame . You're looking specifically for duplicate frames or gaps in motion (jumps) .
I added an edit to my post above - make sure you read the part about expectations for professional compression. Don't get your hopes up high - the biggest obstacle you're facing is low bitrate MPEG2. A professional compressionst can do a few tricks , but nothing that will magically make it look drastically better at that bitrate . If you're willing to go DVD9 as suggested in your other thread - that would help