Video quality poor after AVI conversion

[peterhun]

An AVI is say, 700Mb. Using ConvertxtoDVD the resultant vobs are 4.2Gb (using Best rate) and the picture quality is "dotty" looking, whereas on the avi file it looks quite OK.
What format should I convert to that will give the best picture quality as close as possible to the original avi and burned to Disc.

[guns1inger]

Your avi file is hyper compressed, full or artifacts, and nowhere near as good as you think it is. When it gets converted to DVD and watched on a television, all the flaws are exposed.

You will get slightly better quality if you filter it with some avisynth filters and encode with a good quality standalone encoder - but it take about 4 - 5 times as long to process.

Or you can buy a Divx capable player, but the file as a data disc, and play it without conversion. You will still see the same flaws, but you wont have made them any worse.

[peterhun]

This is all pretty new to me. If the avi is 700Mb and a VCD contains a movie at max 800MB then would the same quality as avi be maintained as a VCD since we are keeping it at roughly the same amount of data bits and not blowing it out to 4Gb? Just a thought!

[FulciLives]

This is all pretty new to me. If the avi is 700Mb and a VCD contains a movie at max 800MB then would the same quality as avi be maintained as a VCD since we are keeping it at roughly the same amount of data bits and not blowing it out to 4Gb? Just a thought!

No. This is not a correct statement.

The problem is you cannot compare the bitrates for various formats as a 1:1 ratio.

Your AVI files are MPEG-4 format (probably XviD or DivX). This format needs less bitrate to look "good" than say MPEG-2 which needs more bitrate to look "good". MPEG-2 is what the DVD Video format uses.

VCD looks like crap even if you use a super high quality source. The problem is that the bitrate is very low for MPEG-1 and the resolution is crap as well.

Perhaps your best solution is to buy a DVD player capble of MPEG-4 (XviD and DivX) playback. One popular yet inexpensive choice right now is the Philips DVP-5140 which can be bought from WALMART for about $50 US Dollars.

- John "FulciLives" Coleman

P.S.
I just looked at the Philips website (the Australian version) and the model you would want is the DVP5965K/75

It seems that this model is the Australian version of the Philips DVP5960/37 (USA Version). It appears that the DVP5140/37 (USA Version) is not available in Australia.

[guns1inger]

Nope. VCD uses mpeg1 at a resolution about a quarter of what your avi probably has, so it is throwing away 75% of the image data to begin with.

You have three choices :

1. Buy a new player that plays the avi files as-is

2. Convert them to DVD and live with the results, or

3. If you want DVD quality, import the DVD from where ever it is available.

Downloading movies in Divx/Xvid format of 700MB in size is not going to get you DVD quality, or even near-DVD quality.

If you really want to understand why, you need to

* Read What is DVD (top left corner of this page)

* Look at the true resolution of your avi file using avicodec or g-spot 2.60 to compare

* Do some reading about the different codecs and understand why some are more efficient than others (and therefore why 90 minutes can look reasonable in 700MB when encoded with an mpeg-4 codec, and not so good at 3GB when encoded with mpeg-2)

* Come to the realisation that it is far easier to spend $39.95 at your local DEC store to buy an avi capable player and put 6 of these files to a disc without converting.

Edit : Damn it, John, beat me to it.

[peterhun]

Thanks guys. If I choose the last option and put a few avi's onto 1 disc would I be able to use some app that would give me a menu to choose what to play or would the Player only see the data as 1 continuous file?

[FulciLives]

Thanks guys. If I choose the last option and put a few avi's onto 1 disc would I be able to use some app that would give me a menu to choose what to play or would the Player only see the data as 1 continuous file?

You would burn as a DATA CD or a DATA DVD and the MPEG-4 capable DVD player will have it's own (all are very simple) file menu system to allow you to pick which file to play.

The files are usually listed in alphabetical order. It is best to rename the file to the standard 8.3 filename standard. So what I mean is 8 characters followed by .AVI like, "filename.avi" because many of the MPEG-4 capable DVD players do not support "long" file names.

- John "FulciLives" Coleman

[guns1inger]

My LG thankfully does, although not a full character set.

I would aviod buy one of the el cheapo's from Strathfield or similar. DEC's model is reasonable. If you can afford, most of the brand names have Divx/Xvid capable players. Pioneer have a couple of models now that also have HDMI and HD up-conversion built-in (then you will really see how bad a 700MB movie can look)

[peterhun]

Thanks, I'll give these a shot and see how it turns out. I'm getting some hard to get 40's and 50's movies that are mostly Public Domain. Being B/W I'd most likely get a few onto 1 disc.

[thecoalman]

To add a little more to what has already been mentioned what steps or amount of steps taken in between can have a profound affect. Here's a simple example:

DV-AVI > 3000kbps MPEG


DV-AVI > 8000kbps MPEG > 3000kbps MPEG


They are both taken from files with same exact bitrates the only difference being is the second one went through 2 encodes. One place you would be taking a hit on quality is that your AVI file is probably a non-standard DVD resolution and is being scaled up. I haven't made any comparisions but I wouldn't doubt you would get better quality going directly from an excellent source to a low resolution, low bitrate MPEG as opposed to first creating an ittermedite DIVX then scaliing up to a high bitrate, high resolution MPEG as you are doing.

[guns1inger]

I also suspect that many of the file of which you speak are taken from public domain releases of these movies, which often are taken from 1 inch tape masters, not film, and poorly encoded. I know, because I own or have downloaded several of these myself. The originals that I own claim to come from 35mm film masters, but they are so poorly encoded and soft of image that even if it's true, you wouldn't know.