Video data rate and quality

[Ap]

Hi i have just started to backup a dvd on my harddrive to xvid avi And i basically have a few questions.I use dvd decrypter and Simpledivx.So far i have made 5 copies of the movie Platoon each time trying new things to decrease size and make a better looking picture.The first time i did it i pretty much kept everything default and was somewhat unhappy with the picture but the sound was wonderful,when actions begin like the vietcong running thought the jungle i could see lotsa pixels.The 3th time I kept the auto-retrieve croping and resize info to 640 as i was told,Then i started to bring the compression file size up from 1400mb to 1600mb as i did this, the bitrate went up and it nolonger said very good quailty i kept bring it up intill it said dvd quailty,i also droped the audio down from 448 to 192 ac3.After it finished i check out the movie the picture was a little bit better but still not what im aiming for.I have seen a few downloaded dvd rip xvid and those simply look better.One thing i noticed when the bitrate went up higher(dvd quailty) and after it was done,i checked out the video data rate and this was lower than the first time i did it even tho the bitrate was higher?I was told that a higher video data rate was a better looking video or is this false?Also what kind of bitrate should i be aiming for the first time i did it was 1184 kbps then when i took it up it was at 1674 kbps (so called dvd quailty)should i be aiming higher than this?Whenever i see anything running this is when the video gets ugly and pixely.Whould any of these settings help,Xvid advance settings: Very highquality,Global motion compensation,Quarter-pixel,Enable lumi masking,Enable chroma motion all are unchecked as i have no idea what these settings are and what they will do.I guess i have alot of questions.

[thecoalman]

The higher the better. Go higher, not sure about divx but for mpg 4000 and up. I usually go as high as possible, as long as it will fit on the disc.

[Ap]

I will not be putting my xvids on disks so no need to worrie about that.I cant find out what the final size of the video will be,example under the compression tab i have file size set to 1600mb,but the final movie comes out to 938mb for a 2 hour movie.Shouldent it be 1600mb?

[junkmalle]

Rather than using constant bitrate, use two pass variable bitrate. That allows the video to use more bitrate when needed, less when not.

Xvid has a nice single pass "quantization" mode -- essentially constant quality. The drawback is you don't know exactly how big the file is going to turn out. I usually use quantization settings between 3 and 4 (higher value --> lower picture quality). This gives good picture quality and overall bitrates between 1000 and 2000 kbps (depending on the video).

[Ap]

Under the codec tab i have Create a 2-pass video file with ac3 audio.So are u saying that when it is set to 2 pass i dont need to worrie about the bitrate settings?

[junkmalle]

It's been a long time since I used Divx. I always use Xvid now because it works at least as well and is open source. I also don't use SimpleDivx so I can't say anything about that programs particulars.

I think the way it works in Divx is you set the desired average bitrate during the first pass. During the second pass you adjust the Modulation setting. I think for most videos you can just leave it in the middle.

By the way, I don't recommend using Global Motion Compensation or Quarter Pixel. Most hardware Divx players can't handle those.

[junkmalle]

Sorry Ap, I had your thread mixed up with another one. I see you're using Xvid. Just try using the Quantization mode and don't worry about bitrates. I usually use settings between 3 and 4. Sometimes I'll go has high as 7 if I need to really squish a video (higher Quantizatino settings give more compression). I can usually shoot for a 90 minute movie in a 1 GB file.

[Ap]

Hardware dvd divx players?i will not be buying one or using one,i simply want to watch it on my computer with the best video quality possible.I am trying to figger out how to do this proper, right now its been trial and error with each attempt taking 4 hours.I hope some of the questions i asked will help in that.I dont plan to use divx but xvid i perfer it better.

[Ap]

I was a little jumpy on the last post