noise added to video during rendering

orpioneer · Post by **orpioneer** » Sat Apr 11, 2009 6:50 pm

I thought I saw some similar reports of this type of problem a while back, but the search function on the forum doesn't seem to be working for me today. The posts that come up when I search have nothing to do with audio problems.

Anyway, I have created a short video that sounds fine during editing until I go the the Share step in VS X2 Pro and create a video file from it (using Same as Project Settings). The resulting file has a lot of loud popping and crackling in it. I've gone back to my original project file a couple of times and tried applying both the Remove Noise and the Clicks Removal audio filters. Each time I created a video file afterward but the loud popping and cracking still occurred when I played the video file.

The project file consists of some edited video clips with various scene transitions and titles at the beginning and end. It also has a music track which seems to somehow relate to the problem. The music track is a wav file created in SonicFire Pro using some of their smartsound music and sound effects. The track sounds fine when played in sonicfire and sounds fine when added to the project file for my video in VS 12. It's only when the project is converted to a video file that I get the loud popping and cracking, which usually occurs in the vicinity of the sound effects, even though they aren't particularly loud effects (low rumbles and air whooshes generally). But wait, there's more. When I take this same video and use a different music track with it, the resulting video file has no such problems. However, that alternate music track was also created in SonicFire Pro, and has some of the same sound effects. So, I'm having a hard time blaming this on SonicFire, especially since the problem doesn't show up until I start using the music in VS and try to create a video file. Any thoughts would be appreciated. Like I said, I seem to recall other people seeing audio problems crop up after rendering and I'm hoping there is a simple fix.

My project properties are:
NTSC drop frame (29.97 fps)
Microsoft AVI files
24 bits, 720 x 480, 4:3, 29.97 fps
Lower Field First
DV Video Encoder -- type 1
DV Audio -- NTSC, 32.000 kHz, 12 Bit, Stereo

Post by **Ron P.** » Sat Apr 11, 2009 7:03 pm

My project properties are:
NTSC drop frame (29.97 fps)
Microsoft AVI files
24 bits, 720 x 480, 4:3, 29.97 fps
Lower Field First
DV Video Encoder -- type 1
DV Audio -- NTSC, 32.000 kHz, 12 Bit, Stereo

I've found that for some reason using 12 bit 32kHz audio is not liked by some NLEs. Try converting your audio to 16 bit 48.000kHz. You can do this in a couple of ways. The easiest would be to just render another video file, however use the 16 bit audio settings. Your video will not be recoded, just the audio.
I have a few older clips that I had inadvertently recorded using 12 bit. After finding this problem, and changing it in my Digital-8 camcorder, I no longer had the audio distortions..

orpioneer · Post by **orpioneer** » Sat Apr 11, 2009 7:58 pm

Vidoman,

You are awesome!! It took me a few minutes to figure out how to change the bit rate setting but once I did and created a new video file it worked like a charm. There is still just a hint of crackle but it's too faint to be noticed by anyone not listening for for it. Previously it was this explosive popping and cracking.

Is this 12 KB setting something I need to change in my preferences for future video capture onto my computer? My video comes from a Panasonic (PV-GS120) camcorder using DV tape and most of the clips I have on my computer were originally captured using VS 10 Plus.

And sorry to be such a newbie but what is an NLE?

Thank you so much for the quick response and the great fix!!!

ORpioneer

Trevor Andrew · Post by **Trevor Andrew** » Sat Apr 11, 2009 8:45 pm

Hi

The 12 bit is created during camera recordings.

You need to change the audio settings on your camcorder from 12 to 16 bit.
Then subsequent recordings will be in 16bit audio.

Black Lab · Post by **Black Lab** » Sat Apr 11, 2009 9:04 pm

And sorry to be such a newbie but what is an NLE?

Non-linear editing.

orpioneer · Post by **orpioneer** » Sat Apr 11, 2009 9:45 pm

Trevor,

After seeing your post I dug out my video camera manual, I had no idea I could alter any of the data settings on the camera itself. But I see instructions for finding the menu screen where it sets the audio capture rate. I am wondering how this will alter the size of my files though, both on the tape and on my PC. I often tape festival performances that run for an hour, which I can just barely finish filming before my DV tape runs out. And will I hear an improvement in sound quality at the 16 bit 48 KHz?

Trevor Andrew · Post by **Trevor Andrew** » Sun Apr 12, 2009 10:08 am

Hi
Capturing from a digital Mini-Dv type camera via firewire produces DV-Avi files.
This data is created in the camera during recording.
Capturing is actually transferring the data to the pc.
No re-coding takes place, what you have on the camera is what you get on the pc. (assuming there is no problems with the firewire card/cables) You have the option to choose the DV type, DV Type-1 is recommended, (view options cogwheel.)

The files are quite large at 13 Gb per hour. But if you want quality then this capture is the best method you can use.

Changing the audio from 12 to 16 will have no noticeable affect on the size of the files.
As for sound quality, I wouldn¡¦t have thought that you will hear any improvement, but I may get corrected hear.
I have a GS400 similar to your camera and the sound quality is simply great.

Once you have edited the Dv-Avi files the project is converted to a Mpeg file which is subsequently used to burn a DVD, Its at this point that you choose the Mpeg bit rate to create a file that will fit a DVD.
Anything under 60 minutes and there is no problem, above 60 and the bit rate may need reducing.
If you are using Lpcm audio then changing to Digital Dolby will create smaller files.

orpioneer · Post by **orpioneer** » Sun Apr 12, 2009 5:22 pm

Many thanks to all of you for the very helpful information on this. I've gone ahead and changed the audio record setting to 16 bit on my camera, and hopefully that will prevent problems from cropping up again. And last night I successfully created my first DVD using VS X2 Pro (I've used VS 10 Plus up until recently) and it sounds great. Actually, I should say that I successfully created the disk image, not the DVD. Corel crashed in the wee hours of the morning at 99% completion, so I used Roxio to finish burning the disk. (Good to know Roxio is good for something.) Hopefully that approach won't become the norm!

Post by **Ken Berry** » Sun Apr 12, 2009 10:51 pm

In point of fact, many of us here use third party software to actually burn the DVD -- not because of any inherent problem in the VS burner, but because it is often more convenient. VS gives you no real option to burn numerous copies in the sense of two now, and 3 in two days, and a dozen next week. On the other hand, producing an ISO image file or, as I do, a DVD Folder (Video_TS), and simply run that in Nero or Roxio or similar program to carry out the burn. I prefer the DVD Folder route, by the way, as it is easy to play (and thus preview) in a DVD software player like WinDVD or PowerDVD... With an image file, you can do it, but you have to have yet another program to first 'mount' the image on a virtual drive, and then a software player can see it...