"Mosquito Noise" in video after .avi render???

pjprod wrote on 12/24/2003, 7:20 AM
I rendered a .avi file that had serveral tracks of audio and video. Some tracks also had PNG and TGA files. I rendered best quality, NTSC DV Template. After render, I notice mosquito noise in some of the footage. It looks like a tiny swarm of mosquitos in certain areas of the footage. It seems like it is video compression artifacts, is this normal with DV 25 editing??? The footage captured into the computer is DV, shot on a professional 3 ccd camera and the footage is clean and crisp. Is there any other settings i should be aware of???

Any Thoughts would be appreciated...John

Comments

rebel44 wrote on 12/24/2003, 9:24 AM
I would said that some noise(electrical interference) got to you durring capture and show up after render. See if you can expand the timeline and see where the noise show up. You my be uble to cut off that portion or quite down.
Softcorps wrote on 12/24/2003, 9:32 AM
John,

It's possible that there is mosquito noise in your render depending on the content of the footage. Go to the following link and see if what's described is what you're seeing.

DV Picture Artifacts

John
pjprod wrote on 12/24/2003, 9:51 AM
John...this is exacty what i am seeing, it is showing up near my face during a lower third CG. Is there anything I can do to quiet this down??? Do you recommend using some guassian blur or is there something not set correctly??

Thanks for your help...John
sbloombaum wrote on 12/24/2003, 11:14 AM
Oh, so THAT'S what you're seeing! (Somehow I thought of white specks)

We're talking compression artifacts.

Assure that there are no source materials that display them.

Assure that there are no extra compression/encoding steps in your workflow.

ESPECIALLY assure that DVDA is not recompressing an MPEG-2 file that was already compressed in Vegas. (note that you should either render to the Mainconcept MPEG-2 template for DVDA OR to uncompressed DV and let DVDA do the compression)

Finally, a low bit rate setting in your MPEG-2 compress in Vegas or DVDA can produce this result.

If all this "Assure this" and "assure that" leaves you clueless, post your detailed workflow, including any compression steps, how long your material is, how long vegas took to output it, and how long DVDA took to compress.

BTW, blurs would only help if the artifacts are in your source material.
farss wrote on 12/24/2003, 1:24 PM
Welcome to the world of DV!

These artifacts are just part of the world of DV. Other things to watch for are how you are feeding the signal from the player to the monitor. Composite video introduces its own artifacts as well so you can spend a lot of time chasing down problems. If you run into the later using the Broadcast Colors filter in VV will help a lot. Won't do anything for DV artifacts though.

Adding VERY small amounts of blur might if you put that in the TL and then render directly to mpeg do the trick. If you render back to DV and then encode that you'll need so much blur that you'll make everything so soft. Other option if you've got heaps of disk and time would be to render out to uncompressed AVI with the tiny amounts of blur. What you really need I think is to smooth the chroma more than the luma and render with that straight to either mpeg or uncompressed AVI. Don't know of way to achieve that in VV though.

BTW I've noticed that the filters in most TVs seem to get rid of many of the DV artifacts. They can look horrid on precision monitors up close but it looks damn near perfect on the TV.
AudioIvan wrote on 12/24/2003, 7:03 PM
Exactly farss,that is the native quality of the DV.
Try some AVISynth filtering to remove the DV noise before rendering final product.Also depends on the codec that you capturing the video.Some of them are known to produce artifacts & chroma,luma interference.Try capturing with software that will allow you to sellect codec of your choice.
Huffyuv or Mainconcept DV .v.2.4.4 are more than good.
Hope this helps,
AudioIvan
farss wrote on 12/24/2003, 9:37 PM
Unfortunately there's not much you can do about the codec in the camera. There are some filters made by Formatt that apply a very gentle blur that can help, in other words optically smooth out the image before it gets to the CCDs and the encoder.