Black blocks = compression artifacts?

[pixelhooer]

Hi,

***I have searched google, this forum and read the stickies with no luck.***

I think I'm having problems finding an answer to my problem because a) I don't know enough about digital cameras, b) don't know the correct technical jargon to search for.


I am getting a lot of artifacts (????) when I am filming something very bright, such as fire, streetlamps, and I have also had this issue with white PVC. Any really REALLY white thing will just flicker black blocks during a shot. If I watch a clip on my digital camera/handycam (yeah -- it's baller - i know) it looks fine, but when I transfer the clip to my computer, and watch it in VLC it gets these blocks in the ultra bright areas. Then when I convert the files the problem gets worse.




I asked my professor (note: not a film/photography professor) and he said the camera's light sensor was being overloaded (?) He also mentioned there is a way to fix this problem in After Effects, but couldn't go into further detail. So, if anyone knows what plugin or method I can use to correct my video, or even what the technical term for this mess is, please let me know.

It's not that my videos are unwatchable, it's just that I'm anal and it's distracting while watching them, and I'd like to fix it, or better yet, avoid it all together.

Thanks in advance.


EDIT: I may have been a little overzealous in my posting. So this may be some kind of video noise that can be corrected with TMPGEnc as stated here: https://www.videohelp.com/oldguides/dazzlecapture#filters

Now the question I'll pose, since I'm using a mac, what program is recommended in lieu of TMPGEnc?

[filmboss80]

Certainly, it COULD be compression artifact, though you don't specifically say what your format is (dv-avi, mpeg, mp4, etc.). The greater issue -- which is certainly contributing to the problem -- is recording an ultrabright image in an ultradark setting. The camera's auto iris is opening up for the dark surroundings, thus over-exposing the bright image. If you have manual control over your iris, you should use it. Otherwise, provide fill lights for the dark areas, and use a low-contrast lens filter.

Quite frankly, this is poorly-shot footage, and you need to know the limitations of your camera.

EDIT: is this analog or digital footage? You may be able to turn down the IRE level during capture to computer. Let us know how you're getting it into your Mac.

[poisondeathray]

The black blocks aren't typical macroblocks. If you look at the periphery (e.g. around the shoes, around the walls) - those are typical macroblocks and deblocking filters may help (but the side effect is they tend to blur the image, and your image quality already sucks)

In contrast, the black blocks have no information. You can only "borrow" information from neighboring pixels. You might use the clone stamp tool in After Effects to do this. This would be similar to "airbrushing". No filter will magically fix everything, if you want even bad results, there will be a lot of manual manipulation

I would just get a better camera ; it's probably not worth your time to salvage this

[pixelhooer]

Certainly, it COULD be compression artifact, though you don't specifically say what your format is (dv-avi, mpeg, mp4, etc.). The greater issue -- which is certainly contributing to the problem -- is recording an ultrabright image in an ultradark setting. The camera's auto iris is opening up for the dark surroundings, thus over-exposing the bright image. If you have manual control over your iris, you should use it. Otherwise, provide fill lights for the dark areas, and use a low-contrast lens filter.

Quite frankly, this is poorly-shot footage, and you need to know the limitations of your camera.

EDIT: is this analog or digital footage? You may be able to turn down the IRE level during capture to computer. Let us know how you're getting it into your Mac.

Note: Still image above is from a regular point-and-shoot digital camera that records video, so yeah, image quality is predictably poor.

Currently my video format is muxed MPEG footage from a sony handycam (DCR-SX44) that is less poor. However, it requires me to convert it from MPEG to a mp4/avi/etc -- I'm not picky -- basically any format that will separate the audio track from the video track so I have audio when editing.

As for transfer, I just plug in the SD card, or connect the camera to my mac and drag onto my hard drive through Finder.

Shooting a bright light in dark surroundings makes for a sensible problem. But night shots are necessary for me at this time, because flood lights and extension cords are not conducive to being inconspicuous.

if you want even bad results, there will be a lot of manual manipulation

i lol'd -- but thanks for mentioning the clone stamp