Making XVID videos with VirtualDub: output files w/huge file sizes (~1GB+)

[maskingtape]

I have a DVD with footage of four concerts on it and I'm trying to rip the DVD to my computer and then split up the four shows into four separate video files and upload them to the net. I've done the first part but the issue is that each of the four movie files is inexplicably large in file size...too large to be uploaded anywhere online. So I'm coming here to try and figure out why they're so big and how I can get them down in size (without losing the video quality).

My process was this: I put the DVD in, ripped it to my computer using Xilisoft DVD Ripper Ultimate 5 and had a two-hour-long XVID video file of the DVD that was 2.45GB in size. I then opened that video in VirtualDub and got an error message. I googled the error message and found that in order to get Vdub to recognize/open the video I had to type in "XVID" next to "Force video format FOURCC code to:" in the Import Options since the file was labeled with lowercase "xvid" which Vdub didn't like...I'm not sure if this has any relevance to the file size issue or not but I figured I'd mention it.
Anyway, once I did that I opened the file, cut the vid down to just the first show (24 minutes long), cropped out the black edges (making it 640x480), chose "Xvid" as the compression method and saved the video. The result was a 24 minute Xvid AVI file that was 979MB in size...practically 1GB. I've never experienced a file being so large even after being compressed with Xvid so I'm not sure what happened. Every time I've downloaded a TV show that's 22 minutes in length and encoded with Xvid the file size has always been around 175MB, so clearly something is "off" somewhere to make a 24 minute xvid file 979MB.

After that I saved the other three shows using the same method.
The second was 20 minutes long and 1.35GB in size.
The third was 16 minutes long and 773MB in size.
The fourth was 50 minutes long and 1.58GB in size.

It doesn't make sense how the 2 hour long source vid can be 2.45GB and a 20 minute portion of it (1/6th) can be 1.35GB when the encoding is the same. So why are these videos coming out so large and what can I do to make them smaller?

Btw, if it helps, here are the specs on each of the 5 videos (the first source vid and the 4 individual vids I took from it), copied from MediaInfo:

http://textsnip.com/text/vid1
http://textsnip.com/text/vid2
http://textsnip.com/text/vid3
http://textsnip.com/text/vid4
http://textsnip.com/text/vid5

Thanks in advance for any and all help!

[guns1inger]

Bitrate

Filesize = Running Time X Bitrate

The higher the bitrate, the bigger the file

[creamyhorror]

The result was a 24 minute Xvid AVI file that was 979MB in size...practically 1GB. I've never experienced a file being so large even after being compressed with Xvid so I'm not sure what happened. Every time I've downloaded a TV show that's 22 minutes in length and encoded with Xvid the file size has always been around 175MB, so clearly something is "off" somewhere to make a 24 minute xvid file 979MB.

1. You have a misconception that encoding with a particular method always results in a particular bitrate (i.e. filesize per hour). It does not - you set the bitrate or quality level yourself when you encode. You probably haven't configured XviD (in Vdub) to the bitrate level you want.

2. You shouldn't be ripping to XviD via Xilisoft and then encoding it to XviD again. This degrades quality because of the double encode step. Use a ripper/encoder that allows you to do the cropping and cutting and encode directly from the DVD source. Others may have suggestions in this area (perhaps AutoGK?), but I'm only familiar with Handbrake (which encodes to x264 and not XviD).

[maskingtape]

Bitrate

Filesize = Running Time X Bitrate

The higher the bitrate, the bigger the file

Ah, alright

Well the bitrate counts for the four videos are 5,493 Kbps, 9,402 Kbps, 6,326 Kbps and 4,281 Kbps respectively and the bitrate count for a random unrelated XVID video I have on my computer is 868 Kbps so that's a rather large difference.

How can I lower the bitrate to something more normal?

[guns1inger]

For what you are describing above, the best process is to rip the DVD to your HDD with DVDFab HD Decrypter, then use AutoGK or AVI.net to create your Xvid files. There is no place for xilisoft software in a quality video chain.

If you do want to dabble in virtualdub/xvid, start by configuring Xvid for Constant Quality encoding with a value of 3. You won't be able to guarantee a filesize, but you will get the same quality throughout. Test various Q values until you find the right compromise between quality and size.

[maskingtape]

For what you are describing above, the best process is to rip the DVD to your HDD with DVDFab HD Decrypter, then use AutoGK or AVI.net to create your Xvid files. There is no place for xilisoft software in a quality video chain.

If you do want to dabble in virtualdub/xvid, start by configuring Xvid for Constant Quality encoding with a value of 3. You won't be able to guarantee a filesize, but you will get the same quality throughout. Test various Q values until you find the right compromise between quality and size.

I ripped the DVD to my desktop with DVDFab HD Decrypter and I now have a VIDEO_TS folder with 10 files in it: 2 .BUP files, 2 .IFO files and 6 .VOB files. What exactly am I supposed to do with AutoGK to get these to turn into an XVID video file of the two hours of footage?
Sorry to be so clueless about this but in the past I haven't gone through these steps so I'm not sure what to do.

[guns1inger]

Open the IFO file in AutoGK and autoGK will show you the titles within

[jagabo]

Xvid's default setting is single pass target quantizer with a quantizer of 4. That is a constant quality encode with moderate quality. The video will turn out whatever size is necessary to achieve that quality. The final file size will vary depending on the source. There can easily be a 10 fold difference. See the videos in this post:

https://forum.videohelp.com/threads/295672-A-problem-for-video-experts?p=1811057&viewfu...=1#post1811057

If you switched Xvid to bitrate based encoding then the final file size is dictated by the chosen bitrate, as others have pointed out.

With quality (quantizer) based encoding you know what the quality will be but you don't know the size. With bitrate based encoding you know what the size will be but you don't know the quality.

[maskingtape]

I opened the IFO file with AutoGK and after a few hours it managed to produce another 2 hour xvid video of the contents of the DVD. This one is 11.2GB in size (as opposed to the 2.45GB file from Xilisoft), although the dimensions are different (the black borders on the sides are gone) and the audio is a bit louder and clearer.
I tried splitting up the footage of the shows into 4 separate video files again (using the 11.2GB file from AutoGK/DVDFab) with VirtualDub and the file sizes are even larger than before; the first video (originally 979MB) came out as 1.85GB and the second video (originally 1.35GB) came out as 2.30GB. The bit rates of the three videos (the full DVD video and the two shows trimmed and produced with Vdub from it) are also significantly higher than the original files.

Here's the MediaInfo specs on them:
http://textsnip.com/text/dvdfab1
http://textsnip.com/text/dvdfab2
http://textsnip.com/text/dvdfab3

So, while using DVDFab+AutoGK did help improve the audio quality and fix the dimensions, the video files are still far too big in file size to be uploaded to the net.

What are my options (if any) in terms of reducing the file size on these videos (under 1GB would be nice, under 500MB would be ideal) without greatly diminishing the quality?

[jagabo]

You've already been told what to do: use a lower bitrate if you're using bitrate based encoding, or a lower quality (higher quantizer) if you're using quality based encoding.

[guns1inger]

You can also set a fixed filesize in AutoGK, so if you want 200MB, tell AutoGK to output a 200MB video.

[creamyhorror]

What are my options (if any) in terms of reducing the file size on these videos (under 1GB would be nice, under 500MB would be ideal) without greatly diminishing the quality?

You seem not to have grasped that you have to set the bitrate level yourself. The program (whether AutoGK or VirtualDub) doesn't determine it - you do! Look for the settings, or find a guide.