Standard DVD Bit Rate for 352x240 vs 720x480

[CaZeek]

Hello,
I think I already know the answer to this, but either way.. The standard DVD bit rate for 720x480 is 8000 kbps, right? Therefore, would the same level of quality (with respect to the resolution) for 352x240 be 4000 kbps? Thanks!

[CaZeek]

I also have a follow-up question. Is there any calculator or some way of figuring out what the equivalent bitrate for an MPEG-2 would be for a DivX 5.1 compressed AVI? Thanks again.

[FulciLives]

In my opinion ... based on my testing ... Half D1 resolutions (352x480 NTSC or 352x576 PAL) don't MAX out the bitrate until around 5000kbps

At that point ... raising the bitrate any higher ... seem to have no benefit.

If the content I'm encoding is short enough to use 5000kbps then I often do Half D1 with a CBR of 5000kbps

Makes life easy and fast since you don't have to do 2-pass VBR as often with Half D1 resolutions.

- John "FulciLives" Coleman

[teegee420]

Hello,
I think I already know the answer to this, but either way.. The standard DVD bit rate for 720x480 is 8000 kbps, right? Therefore, would the same level of quality (with respect to the resolution) for 352x240 be 4000 kbps? Thanks!

If I had to guess I would say that a 3000kbps bitrate is the max that can be reasonably utilized for 352x240. I agree with FulciLives's assessment of Half D1 too.

I also have a follow-up question. Is there any calculator or some way of figuring out what the equivalent bitrate for an MPEG-2 would be for a DivX 5.1 compressed AVI? Thanks again.

As far as I know there is no such calculator. The reason being that there is no direct link between Divx and mpeg-2 bitrates. Mpeg-4 is a completely different ball of wax and you must assess bitrate amount qualities independently from mpeg-2.

[Firk99]

As you only have 1/4 off the resolution, a quarter of the bitrate should be enough, however you should try it first with a short clip, and compare it with a clip encoded with a higher bitrate.

[RabidDog]

I think you are wrong full dvd d1 max 8000 as you say BUT 352x288 is quarter D1 ergo only needs quarter of the bitrate 2000k but obviously you have to try it and see. divx5.1 at bitrates above 1200k will look very good
@ 2000k would be same as original.. IMO
( Half D1.. 352x576 should be 4000k)

[thor300]

I havent tested this so much, but with 352x240 MPeg2 i mean i can see a noticeable quality loss at CBR 2400. Even 2800 is still not quite as good as it could have been, but then again there is still no lossless conversions.

[FulciLives]

I havent tested this so much, but with 352x240 MPeg2 i mean i can see a noticeable quality loss at CBR 2400. Even 2800 is still not quite as good as it could have been, but then again there is still no lossless conversions.

Yeah but 352x240 is going to look like shit at 8000kbps video bitrate because you just tossed out half of your resolution (480 to 240).

This results in a very unpleasent "jaggy" look etc. that no amount of bitrate can help.

Half D1 is the lowest resolution you should consider.

- John "FulciLives" Coleman

[thor300]

Yepp fulci, im not that stupid, i wouldnt convert a DVD to any less than half D1. These vids were originally DivX3 low motion AVI with VCD resolution, and the result looked like a little degraded as MPeg2 2800 CBR compared to the AVI file.

[adam]

I don't have any problem using 1/4 D1 on some extras and things like trailers. It gives you roughly VCD like quality, which is good enough for me for just a trailer. But for an actual movie, yeah I wouldn't even consider half D1 anymore.

[FulciLives]

Yepp fulci, im not that stupid, i wouldnt convert a DVD to any less than half D1. These vids were originally DivX3 low motion AVI with VCD resolution, and the result looked like a little degraded as MPeg2 2800 CBR compared to the AVI file.

Well this is the first time you mentioned working from files that you did not originate yourself so how was I to know you were dealing with material of this nature.

- John "FulciLives" Coleman