Problem with Blank Frames in Rendering

[Kyle Kepley]

I use Vegas Movie Studio Platinum 8 to convert AVI files to WMV files for posting online. Every single conversion I've done, regardless of the show length or frame rate, inserts a series of black frames at regular intervals. If the frame rate is 30 fps, the black frames are inserted at 00:02:14 intervals. The position moves for other frame rates, but the glitch is always there. This creates a brief blink during the video that is very annoying. Has anyone else ever seen this problem? I can't seem to find mention of it if I google Sony Vegas bugs.

-Kyle

[Mike Kujbida]

A stab in the dark here but are you connected to the net while rendering or is your anti-virus always running in the background?
Either of these two could be doing some kind of "checking" at regular intervals.
Disconnect/disable these and see if you still have the problem.

[Kyle Kepley]

The fact that the blank frames occur at the exact same spot over and over again for dozens of videos would make that theory pretty unlikely, since the background task would have to hold things up at the exact same time every time. I'm pretty desperate though, so I'll try anything. Thanks!

[Ian Stark]

Kyle, I don't have an answer to the problem (which sounds very much like a frame rate issue to me) but if you are desperate to get these files converted, can I suggest you try Windows Media Encoder until you get the problem sorted?

a) It has more control over the wmv encoding parameters than Vegas and b) it's free.

[Ian Stark]

Out of interest, Kyle, are you rendering to exactly the same frame rate as the original material? And how many black frames are rendered every 2s14f? Same number every time? What is the interval at different frame rates?

[Kyle Kepley]

I'll have to do some investigating on the exact details, but I do know that roughly the same number of frames are created at the same intervals for a given frame rate. If I change frame rates, the interval length changes to a new spot but still occurs. For 30 fps, less than a seconds worth of frames were deposited roughly every 2min 14sec. At 25fps the interval got longer but I don't have the exact time on that one.

[Ian Stark]

Ah, I misread your original post - I thought it was every 2s 14 frames that the glitch occurs.

In the absence of any rapid response solutions I think you're gonna need to be exact in the timing (specifying mm:ss:ff) and the number of blank frames inserted for each frame rate. Also, what's the frame rate of the original footage?

Finally, did you try WME? Any success? Another alternative is you try to do the conversion using Windows Movie Maker. That would at least include/exclude Vegas as the culprit.

[Kyle Kepley]

When I make the conversions with other programs I don't get the black frames, so it's only Vegas that is doing this. I could just use WME or other dedicated format converters, but it would be nice if this program that I just paid a bunch of money for actually WORKED for such a simple task.

[Ian Stark]

Sorry Kyle, I mentioned the other programs because in an earlier post you said you were desperate and would try anything. I assumed you had some kind of deadline to meet.

I think you will find that Vegas does actually work for converting files from avi to wmv and this is kinda borne out by the fact that there aren't hundreds of others posting reports of that problem here. That suggests that you are doing something wrong, there is something wrong with your original footage, there is something wrong with the installation of Vegas, or there is something wrong with a plugin you may be using.

Can you please post the .veg file here so we can take a look at the settings?

Also, as I mentioned before, it would help if you can provide specific details of frame rates and the outcomes, the frame rate of the original footage, etc. "Less than a second's worth" and "roughly every 2m14s" is a bit vague. This detail will help someone sort your problem out.

Out of curiosity, are you JUST using Vegas for file conversion or are you doing any editing as well? Have you applied any plugins to the timeline? What are they? The more info you provide the more likely you'll get your answer.

[Bob Hart]

This may be a silly question but. Is your vision HD, HDV and not MiniDV?

Is the filesystem of your computer FAT32 with its filesize limit?

[Kyle Kepley]

Right now I'm just using Vegas for the file conversion, since the quality of the converted video is better than the other programs I have tried. If it weren't for the black frame issue it would be perfect.

I suspect the problem lies in the original footage. I can think of two variables: the frame rate and the codec used in the original. I like to use the Cinepak codec by Radius, which produces the best results. An avi made with Cinepak won't even load into WME though, whereas Vegas doesn't have a problem with it. I'm going to try another avi made with the Windows Video1 codec to see if the black frame problem occurs with that version.

I'll get the frame data too, I just haven't had the time until now. It takes a few hours for my computer to render out a three minute avi file to test with.

[Kyle Kepley]

I tried an avi created with a different codec and it still had the same problem, so it's not a codec issue.

Here's the exact detail of the black frames:
Original AVI file: 00:03:35.18 long, 25fps
Start of black frames: 00:02:41.05
Number of black frames: 3

Both the original file and the converted WMV file were set to a frame rate of 25. Same video has no black frames when converted using Windows Media Encoder. The HD for the output files is NTFS format and not FAT32.

[Ian Stark]

Thanks Kyle.

Couple of follow up questions:

1. Are you using a wmv preset in Vegas (if so, which one) or have you tweaked any parameters (if so what are the settings?).

2. In your earlier post you said 2.14 - has that changed or was that a typo?

3. This is originally SD video, right? Not HD?

To test whether it is just when rendering to wmv when this occurs, do you want to try a render to some other format. Just trying to eliminate possible causes.

[Kyle Kepley]

The 00:02:14 time is when the frame rate is set to 30 fps. The exact time the frames occur on 30 fps is 00:02:14.08, and there are 8 black frames in a row on that on vs. the 3 I get for 25 fps.

The settings are tweaked, but I think I just took the default template and changed the framerate to 25 fps. The following settings were used for the video tab:

Mode: quality VBR
Format: windows media video 9
Image Size: DVD quality (640x480)
Pixel aspect ratio: 1
Frame rate: 25
seconds per keyframe: 3
Quality: 90%

The frame size in the original AVI file is 1280x884x16. The audio track is shorter than the video track, if that matters. Video runtime was 00:03:56.18 while audio runtime was 00:03:35:05 (44KHz, 16 bit stereo, uncompressed).

I tried converting to the MPEG-2 format and the black frames were still there in the exact same place, so it doesn't seem to be specific with the .WMV format.

BTW, if you want to see the converted .wmv videos, there are four of them posted on this webpage:

http://www.showsim.com/showsim/showsim3d.htm

[Kyle Kepley]

I just discovered that the original AVI files have a series of bright red frames at the same spot where the black frames occur after the Vegas conversion. I never noticed this before because the red frames don't cause a visible flash on the screen like the black frames do when viewing the videos. Does Vegas show empty frames as red maybe? I don't see how there couldn't be a red flash visible when watching the original AVI. In the case of 25fps, there's 7 red frames in a row, which should definitely cause a brief red flash when watching the video. But I've watched the exact spot several times and nothing happens.

Vegas just converts the red to black, so the problem is really the red frames in the original footage. Although other converters still don't result in a visible glitch after conversion, so I think I'm just not understanding what is going on here.