Webcam Video Artifacting after/during encode?

[KoolerKii]

Wasn't sure which to put this in, Restoration or maybe Video Conversion.

Hi, I have an issue.

I have an MP4 webcam video file taken with a Logitech C920 recorded with Logitech's proprietary recording software and the video I recorded came out just fine. Example: https://forum.videohelp.com/images/imgfiles/JA3jmQR.png

I make gaming content, so its essentially just a face cam when I overlay it over an uncompressed lossless Lagarith codec recorded gameplay avi video.

But when I scale it down about 75%, and crop the edges out, I get this: https://forum.videohelp.com/images/imgfiles/CIm6FKz.png
Not sure if I would call those artifacts, but frankly I don't know what else to call them, and I can't find anything about it on the web.

And when I get rid of the scaling and cropping, it still stays there despite being full size again. I did some troubleshooting and found out that it happens right after I go below 51% in scaling down. So as a workaround, I encoded a separate file where it was scaled down 51 and cropped, then imported it into the original sequence and scaled it down about 51 and it seemed to work. So I finish the edit, and begin to exporting, except, the exported file shows the blemishes after exporting.

I've also tried different encoding settings, but nothing I tried really made a difference other than the quality. The bitrate is kinda high for 1080p60 as I'm using it for archival purposes. Probably could go smaller but I don't really like messing with the rates. (Not that experienced.)

I have a feeling it has something to do with Logitechs software I use to record it, as I don't know what codec its uses but then it wouldn't make sense because it plays just fine in VLC and Windows media player before put into Premiere.

Here are my encode settings: https://forum.videohelp.com/images/imgfiles/qKAyCG3.png

My PC Specs:
Intel i7 4790k 4.0GHz
Corsair H100i GTX Liquid CPU Cooler
Asus MAXIMUS VII HERO
Corsair Vengeance Pro 32GB
x1 Samsung 850 EVO 1TB SSD
x1 Samsung 850 EVO 250GB SSD
EVGA GeForce GTX 980 Ti SC+
Corsair 850W Modular PSU

Any insight or help will be greatly appreciated.

Edit: I feel its worth mentioning that this didn't happen in my first video of the series I made. This is the 2nd video. Same settings as the first of course.

[poisondeathray]

What does mediainfo (view=>text) say about the recorded file from the webcam ? Sometimes things like VFR (variable frame rate) can give PP (and other NLE's problems)

Try disabling GPU/ Mercury Playback engine and GPU rendering to see if it makes a difference. Sometimes GPU scaling / filters/operations can cause glitches or weird problems. Also check GPU drivers - often they release them quickly, but they are full of bugs. Often older drivers are more stable. But if you disable GPU/ MPE, then the scaling is done by CPU.

[KoolerKii]

I'll try tinkering with those GPU settings you mentioned and will post back if I see any results.


Maybe its the 30fps webcam having problems with the 60fps encode?

Here is the mediainfo:

General
Complete name : D:\Folder\Folder\Working\Video 4.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom (isom/iso2/avc1/mp41)
File size : 889 MiB
Duration : 20mn 21s
Overall bit rate mode : Variable
Overall bit rate : 6 105 Kbps
Encoded date : UTC 1970-01-01 00:00:00
Tagged date : UTC 1970-01-01 00:00:00
Writing application : Lavf52.64.2

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : Baseline@L4
Format settings, CABAC : No
Format settings, ReFrames : 1 frame
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 20mn 21s
Bit rate mode : Constant
Bit rate : 6 000 Kbps
Width : 1 920 pixels
Height : 1 080 pixels
Display aspect ratio : 16:9
Frame rate : 30.000 fps
Standard : Component
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Progressive
Bits/(Pixel*Frame) : 0.096
Stream size : 873 MiB (98%)
Encoded date : UTC 1970-01-01 00:00:00
Tagged date : UTC 1970-01-01 00:00:00
Color range : Full

Audio
ID : 2
Format : AAC
Format/Info : Advanced Audio Codec
Format profile : LC
Codec ID : 40
Duration : 20mn 20s
Bit rate mode : Variable
Bit rate : 99.9 Kbps
Channel(s) : 2 channels
Channel(s)_Original : 1 channel
Channel positions : Front: C
Sampling rate : 48.0 KHz
Frame rate : 46.875 fps (1024 spf)
Compression mode : Lossy
Stream size : 14.5 MiB (2%)
Encoded date : UTC 1970-01-01 00:00:00
Tagged date : UTC 1970-01-01 00:00:00

[poisondeathray]

Maybe its the 30fps webcam having problems with the 60fps encode?

Absolutely not. You can mix different frame rate footage without a problem. 30 and 60 are "ideal" companions because PP will just frame double the 30fps footage. And I see nothing that jumps out of the mediainfo report

The other thing that sometimes causes "bugginess" in Adobe is mixed up media cache files. So try clearing the media cache

[KoolerKii]

Ah, right, must have forgot that video interpolation was a thing.

I've cleared the media cache, and turned off MPE. Then I exported a 30 second test clip from the most troublesome area which was the beginning. (The first 5 seconds or so.)

*Video exports*

...and that appears to have fixed it. I'll begin the original encode that is ~20 minutes and will post again saying whether or not it worked. (Hopefully double posting isn't a bad thing here.)

If this does end up working that saves me a lot of time and frustration. If so, I couldn't be more thankful.

[KoolerKii]

Oh man this is confusing. So in the test video its fixed. After I finally exported it, viewed it in VLC it seemed fixed. Yet when I uploaded it to YouTube the artifacts came back. And when I went to go take a look back at the original file through VLC, the artifacts were actually there too. Like as if the first time I played it, it was fine, but the 2nd time I played it, the artifacts came back.

Edit: So I kinda just said "The heck with it" and cranked up the bit rate to 60,000 and uploaded that instead. Seemed to work.I don't know what I'll do in the future.

[poisondeathray]

Check the source file with something else other than VLC. e.g. try MPCHC, potplayer, smplayer etc... Certain VLC builds are buggy

"Flaky" , inconsistent behaviour can also indicate HW problems, like overheating, bad memory, bad PSU, failing storage, ... something to investigate

[KoolerKii]

Source file checks out fine in MPCHC. Didn't really try the others.

I'll run some diagnostic tests on my HW regarding temperature. Its a pretty new build...less than 4 months old and nothing was DOA.

After all that is done, the next time I record another video, I'll see if the problem persists and report back with any findings. Thanks.

[KoolerKii]

Sorry to revive this thread, but the problem still persists and currently I'm just doing the workaround I mentioned above by exporting the webcam file at 51% scaled down, then scaling the scaled down version to 51 again to achieve the 25% I'm looking for. That obviously isn't a very efficient way of doing things.

If anyone else has any insight into what could be the problem, I am all ears.