Video editing advice needed, please...

Off-topic
1

I want to start to learn the basics of video editing because making movies looks really fun and I don’t want to leave all the editing of my movie to my friend (because I want a go too :)…and I suppose it’s a lot of work). I’ve now got VirtualDub which I’ve found great for the really basic things I’ve been doing like cutting the ends off videos and now rotating videos (thanks Phil).

This is what I want to be able to:

  • Speed up video so it looks really fast (for boring bits in videos, not to cheat and make it look like I’m really fast :))
  • Take a whole bunch of different parts of video and put them together into one flowing thing (this is the highest priority for me)
  • Add music
  • Make a song fade away in volume at a certain point (turn a 1:35 song into a little 20sec fragment fading in and out in volume)

They’re the main ones for now. Can VirtualDub do all or any of these? If not, what other programs should I get?

Thanks a lot in advance,
Andrew

p.s. My friend and I are going riding on sunday to start filming for the movie which will probably be about 8min at the most. I’ll try not to make it too boring. It’ll have lots of muni on it.

2

Hey Andrew, Good talking to you on MSN the other day.
I just dont know were I would be without Phil. Firstly he give me the link to MSN Plus, then he gives me that VirtualDub!
Anyway, I would also like the same sort of advise! I figured out how to put music over the top though!

Thanks,
Joe,

P.S, I’ll put my vids in my gallery some time - soon!

3

Did you do that in VirtualDub?

4

VirtualDub isn’t really designed to edit videos together; it’s more of a video processing tool to perform operations on one video. However, being the fantastic program that it is, it can do most things anyway.

Speeding up video
In the Video->Frame Rate option there are a few options that will change the speed of the video. You probably don’t want to go fiddling with the frame rate but the option below that, “frame rate decimation” is good for a crude speed adjuster. “Process every other frame” speeds it up by two, “every third frame” by three, you get the picture. I don’t think you can speed it up any finer than that.

Putting videos together
In the File menu there’s an option “Append AVI segment”. Load the first video then use this to select a second video, then when you save it it’ll stick them together.

I’ve had difficulty with sound synchronisation doing this, but it may just have been the particular videos I was using at the time, they were rather dodgy and full of random errors.

Audio
In the Audio menu select “WAV Audio…”, and up pops a little box asking you which sound file you want to use. I presume it only accepts WAVs; if you’ve got a file of a different format you’ll have to convert it first. Winamp is a dead simple way of doing this; select the Disk Writer ouput plugin…

Fading audio
I think this is where VirtualDub’s limits are reached. I don’t think you can do it in VirtualDub; another way might be to fade the sound first (no idea how to do this though, unfortunately) and then merge it using the WAV Audio bit.

A common way round this seems to be to make the video the same length as the song, so the song fades out or finishes naturally.

As a little extra, some of the video effects in the Video->Filters menu are rather useful. That’s where the Rotate function lives, but also others such as brightness adjustment, greyscale and sharpness adjustment.

Hope that little lot helps!

Phil

5

That’s exactly what I was asking for…thanks a lot Phil!

Andrew

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I’ve tried to speed up video and it seems like I’ll need to change the frame rate. Otherwise I’ll end up with maybe 4fps for something that’s going just as fast.

Just a gneral question too, if I keep saving things along the way when I’m editing them and set the compression to that DivX 5.0 codek thingy will I lose quality each time?

Thanks for all the help. I also put a couple of sections together just then which worked really well.

Andrew

7

If you’re using a codec that does lossy compression then you are loosing quality each time you edit a scene and recompress it.

When I capture video from my VCR I capture it using a lossless codec. The Huffyuv codec from http://math.berkeley.edu/~benrg/huffyuv.html works well. It’s lossless so you don’t loose any video quality when editing a scene. Huffyuv gives you about 2:1 compression. You’ll still end up with some very large files, but it’s better than editing the video in raw format.

If you can handle the large file sizes it would be better to use the Huffyuv codec during editing and only use the DivX codec for the final product.

At very high bitrates (4000 bps) DivX does really well. However, in order to get the best quality and the best sync with the audio you need to do a two pass encoding with DivX. Two pass encoding can be a bit of a pain, but it allows DivX to get better compression and it does a much better job of keeping the audio in sync compared to one pass encoding.

First choice would be to use Huffyuv. Second choice would be to use two pass encoding with DivX at about 4000 bps.

8

Something else I forgot to mention in using DivX as an intermediate format while editing a video.

You can only cut frames and do many other editing functions at a keyframe. A keyframe is a frame that is complete on its own, meaning that it doesn’t depend on past or future frames for additional data. If you want to use DivX as an itermediate formate you should tell it to make every frame a keyframe. This will affect the compression (the file will be bigger) but it will allow you much more flexibility when editing the video.

What codecs like DivX do is take a keyframe and then for the next frame they’ll only encode the differences between the two frames. In video, adjacent frames usually have a lot in common and only encoding the parts of the video frame that change is a lot more efficient. You can read a bit more about keyframes here
<http://www.animemusicvideos.org/guides/avtech/video3.htm>

The Huffyuv codec that I mentioned is different than DivX. The Huffyuv codec does not do any frame differential compression so every frame is in effect a keyframe. This makes Huffyuv very good to use as an intermediate formate while editing video.

Huffyuv will create large files. You can figure on about 5GB or more for every 10 minutes of video at 640x480. Best bet is to use Windows 2000 or Windows XP and use a disk formatted using NTFS (rather than FAT32). With NTFS you can create huge AVI files (10’s of GB rather than tiny 2GB files). With FAT32 you can only create AVI files that are 2GB in size. VirtualDub can work around the AVI file size limitations on FAT32 by splitting the files but that is still not an ideal solution. Best solution is to use a big NTFS formatted disk.

Disks are cheap now. I just put a 120GB drive in my computer so I’d have more room for capturing video and some other stuff.