DVD bitrates and apropiate resolutions

[welsungo]

Hi, I have a doubt I would like to solve. I'd like to know where there
is a manual or a book that explains resolutions and bitrates that are
appropriate for certain type of films in DVD. I understand that is not
the same to create a DVD with CBR at 1600 than VBR at 8000.
Therefore, I would also like to know the resolution of film that is
recomendable for each sittuation (the three or four of the different
and most common qualities). I suppose that a film in DVD at 1600CBR
would be too much, or not? This doubts come up because I have some
films in avi that I would like to have in DVD and as originally are at
1000/1600 bitrates, I would like to find the best way so as to loose
the minimum quality in the transformation.

[ZippyP.]

where there is a manual or a book that explains resolutions and bitrates that are appropriate for certain type of films in DVD.

I don't think there is one, and there's too many variables in order to give hard and fast rules. Good sources can have lower bitrates, home movies need much higher. The best you can hope for is some general guidelines from some of the experienced people right here at this site.

Here's a couple I can offer:

- Use the maximum bitrate to fill up your disk.
- Use MP2 or AC3 audio (instead of LPCM) in order to leave more bitrate for your video.
- Use 352X480 resolution if converting from TV or VHS, it's the closest match.
- 352x240 (VCD) can get up to 7 hours on a DVD, 352x480 (1/2 DVD) up to 5 hours, and 720x480 (D1) about 2 1/2. These are my personal limits.
- I use CBR if the bitrate is high enough but switch to VBR as the bitrate drops. For VCD anything below 1400, 1/2 DVD below 2800 and for D1 5500. That's for good sources, home movies need more as previously stated.

Now, you need to do some encoding and decide for yourself as personal preference is a huge factor. What you play it back on and how fussy you are is what will determine your own limits. Hope that helps a bit and good luck.

Edit, Higher action and more noise will require higher bitrates to keep looking good.

[teegee420]

There's some good information about the relation between Divx and mpeg-2 bitrates here. As you will see, there really is no distinct relation.

[welsungo]

I would like to ask to users more experienced than I, as you, for knowing what bitrate and resolution configuration I ought to use to convert the following divx to DVD:

Video 1:
- Resolution: 624x448
- Bitrate: VBR 685

Video 2:
- Resolution: 480x268
- Bitrate: VBR 833

Video 3:
- Resolution: 720x416
- Bitrate: VBR 1210 kb/s

Thaks.

[teegee420]

This is just my personal preference but I would encode just about any Divx movie using a resolution of 352x480. I don't consider most mpeg-4 avi's good enough to use 720x480. It's only going to magnify the original movie's flaws.

Determining the best bitrate is a little more complicated. You need to use a bitrate calculator such as the DVDRhelp Bitrate Calculator. Use as much as the length of your movie(s) will allow in order to fill up your disc(be it DVD or VCD etc.). For 352x480 I would use a minimum of 2300kbps and a maximum of 6000kbps. Again, that only my personal preference. See what others have to say and run some test clips of your own and decide what is best for you. Good luck.

[welsungo]

thank you but... can I gain quality setting the bitrate at 4000 when the original is set at 900? would not this be a way to loose disk space in the DVD that i would use for another film?

[teegee420]

I'm not sure I understand your question, but re-encoding at any bitrate will not improve the quality of your original file. All you can do is try to maintain the original quality as much as possible. Whether a bitrate of 4000kbps is good enough is really a matter of opinion. What looks good to me might not look good to you and vice versa.

[disturbed1]

You can't gain quality.

The divx file is already at a lower quality than the original. Anytime you compress you lose quality. By compressing again, you lose quality once again. Even with the use of filters, something is always lost. Most noise filters are just a type of blur, when you blur, you lose detail, therefore quality.

Quality can be preserved or almost maintained though, with high quality encoders.

9800-4000 720x480 (may dip to 3000 depends on quality/type of source)

4000-1800 352x480

1800- 352x240

Those are just what I use. 352x480 and 720x480 overlap 3000-4000, because it depends on what source I'm using. TV/VHS caps get 352x480 since these are usually low res/low quality to begin with.


The 720x416 avi would be good for 720x480. The 480x268 352x480. The 624x448 could be either 720x480 or 352x480.

I'd do test encodes of each and compare the quality at different sizes.

When resizing, you generally should not increase the resolution size, it is always better to maintain the same size, or reduce. 720x416 to 720x480 isn't that much of an increase.

You can not compare a divx bitrate to mpeg bitrate, they use different compressions routines and are not the same. A 900 divx is much much better quality than mpeg at 900.

Do a few tests for yourself.