Mike Kujbida
2
COW Coins
Forum Replies Created
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Rick, I couldn’t answer the question myself so I did some searching and came up with the following (credit to John Cline and John Meyer for the info). Hope it helps.
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If the video is under 74 minutes and you’re using 192kbps .AC3 audio, you can just use CBR at a rate of 8 megabits/sec and the encode will be the highest quality it can be.
Two pass is only really valid when you use variable bit rate (VBR) because you need to fit more than 74 minutes on a single layer disc. Using VBR, you set a minimum, maximum and average bitrate. The average bit rate determines the final file size. On the first pass, the encoder analyzes the file looking for places which need a higher bit rate, like those parts with high motion, very fine detail or video noise. It also looks for parts of the video which don’t need as high a bit rate and allocates the bits it can save from these parts to the parts which need them.
It’s a balancing act, take bits from here and allocate them there and over the length of the entire file make sure that the bit rate hits the average that you set.
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VBR vs. CBR will not affect space. The ONLY thing that affects the size of the MPEG-2 file is the average bitrate.
If you set it to, for example, 6,000,000 bps (average), you will get the same file size whether you encode in VBR or CBR. What’s more — and this is the one that surprises most people at first — you will get the same size whether you encode at 720×480, 320×240 or any other resolution.
The key in understanding this is to look at the name of the setting: Bits Per Second. What this says is that the encoder is going to use that many bits for every single second of video. When encoding a higher-resolution video (e.g., 720×480 instead of 320×240), fewer bits are available to create the intermediate “B” and “P” frames, so you get more motion artifacts (e.g., “mosquito noise”), but the video is sharper. It is an interesting tradeoff, and an especially important one to understand when encoding for the web.
It also doesn’t matter what frame rate you use. If you encode the video at 10, 15, 29.97, or 30 fps, the size of the file will still be determined ONLY by the average bit rate setting.
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Are these images that you’ve scanned in or do they come from a digital camera?
My usual rule of thumb is, unless you’re doing extensive zooming in on the image, that the pixel size (ignore DPI as it has no relation to anything in video) should be no larger than twice your project size.
For standard definition video, that would be 1440 x 960 pixels.
If you have images from a digial camera, they’re quite often 3,000 x 2,000 pixels (sometimes larger).
use an app like IrfanView to do a batch size conversion to shrink them down.
If you’re scanning images, I’ve found that 1″ of image = 100 pixels at a scanning resolution of 100 DPI.
This is too small for a standard 6″ x 4″ (W x H) image so, unless I need to zoom a lot, I scan at 150 DPI.
With a 6″ x 4″ picture, this gives an image that’s 900 pixels x 600 pixels which is slightly over the 720 x 480 needed.
This gives you a decent sized image that be zoomed in on a bit without degradation.Keeping the image size down is the best cure for reducing flicker.
You can also use the “Reduce Interlace Flicker” option in Vegas to reduce the shimmer.
Another tip is make sure the images fall in the DV colour range of 16-235. Most (if not all) images take the full 0-255 range. Here’s the fix to change this. Click the FX icon and select “Color Corrector (Secondary)”. In the Preset window, select “Studio RGB to Computer RGB”. Your images are now in the DV colour range so that extreme whites or blacks are no longer an isssue.
If it’s still objectionable, apply a very slight Gaussian blur (vertical only – set to 0.001) to the image. -
Since it’s only 10 min. long, bump your Avg. to 8,000,000 and your Min. to 4,800,000.
BTW, I set my Min. to at least 2,000,000 for any renders I do, even if the video is 2 hr. long.
It does help. -
Allen, I agree with you and Terry that a bad tape batch is the most likely cause.
I’ve been using those same tapes (63 min. only though) for a number of years and haven’t had any problems with them.
Just lucky I guess as I have had bad batches of tapes in the various formats I’ve worked with over the years.I’m disappointed to hear that they’ve been discontinued though as I did like them.
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The changes to make to ensure more consistent DVD levels are as follows (done in Vegas):
Encode set to AC3;
Click on Custom tab;
On the first tab, set diag. norm to” -31″;
On the last tab marked Preprocessing, set the Line Mode Profile and RF Mode Profile mode to “none”;
Save this as a preset. -
It sounds to me like you’re not feeding DVDA already rendered MPEG-2 & AC-3 files which is why it’s taking so long.
The process is entirely CPU dependent so, if you have a slow machine, it’ll take longer than with something like a quad core.
There’s no way to assign RAM to DVDA that I’m aware of and I don’t think a RAM disk would help either. -
The thanks go to Edward for doing these newsletters and making them available to the Vegas community free of charge.
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Edward Troxel has an article titled “Using Masks to Create Side-by-Side Video Comparisons ” in Vol. 5 #2 of his newsletters.
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#1. What format is the logo (JPEG, PNG, PSD, etc.)?
Does the logo have an alpha channel?
If yes, try right-clicking it, selecting Properties – Media and set the alpha channel to Premultiplied.
If there’s no alpha channel, use the Chroma Key FX to remove the black background.
Make sure the logo track is on top of your video clip.
Use Pan/Crop to move it around and shrink it.#2. There are two ways to do this.
The first is to take a snapshot at the desired point (set your Preview window to Best/Full before doing this) and save it as a PNG.
Now drop this PNG at the desired point, drag to desired length and apply the “Sony Black & White” FX to it. Set the FX level as desired.
Place an appropriate sound FX at the desired point.The second is to use keyframes and a Velocity envelope to freeze the video (set to ‘0’ at the desired point).
Using Keyframes once again, apply the “Sony Black & White” FX at that point to turn it black & white. Set the FX level as desired.
Place an appropriate sound FX at the desired point. -
Our teacher is having us do this so that we can have user forum experience.
Hopefully your teacher told you that a part of “forum experience” is checking back periodically to see if anyone answered your question of if someone else posted a similar question.
For example, (I’m assuming) one of your classmates posted the same question a day later and got two responses.
There’s also the “search” function, another valuable forum tool to learn.BTW, check the Explain the main differences between an MPG-1, MPG-2 and an MP4 video format thread for answers.