Resizing with Divx Codec or Vdub ?

[nalooti]

Hi all

1/ i'd like to know what is the best way to resize in terms of quality and performance: doing it with the codec itself or via Virtual Dub?

2/ Also i noticed that Divx 6.2 (balanced) takes more time (almost 3 minutes more for a 400MB mjpeg avi file) to encode than with Divx 5.2 with no distinguishable quality improvment (at least subjectively for me) and just few KB lower file size.
I'm not saying that upgrading is useless but if you don't care all the new 6.2 features, is it worth doing it just for quality issue ?

3/ Are Divx 6 encoded files compatible with Divx5 compatible dvd players ?
I know i could test it but i can only do it on my player, not on all those from my families/friends with which i want to share some personal videos.

Also i'm wondering why in Divx5, 1-pass QB mode isn't available with any Divx certified mode while in Divx6, it is. Is it again a marketing point ?

thanks in advance
nalooti

[check]

1) no codec can resize the image, chances are you are using
2)If you are using target bitrate mode the filesize will be the same and the quality will (theoretically) be better. Whether divx6 is good enough to justify upgrading, only your eyes can tell.
3) yes, divx6 is still MPEG-4 ASP. Of course, there are maximum resolution, bitrate etc that are unchanged from divx5.
4) From what I know, the new CQ/QB mode can restrict maximum bitrate and so on to provide a compliant profile, whereas divx5 QB cannot.

[nalooti]

Hi Check and thanks for your quick reply


1) no codec can resize the image, chances are you are using


Sorry, didn't get it. In Divx Codec configuration, Video tab, you can resize, crop, ... your video.
Seems you didn't finish your phrase. What about resizing with Vdub anyway ? better than the Codec'x config utility ?


2)If you are using target bitrate mode the filesize will be the same and the quality will (theoretically) be better. Whether divx6 is good enough to justify upgrading, only your eyes can tell.

Sorry, forgot to say i encoded in 1-pass QB mode with Quant=4. Is it normal that Divx6.2 takes longer to encode than Divx5.2 ?


4) From what I know, the new CQ/QB mode can restrict maximum bitrate and so on to provide a compliant profile, whereas divx5 QB cannot.

Does that mean that if all my "Divx5.2, 1-pass, QB q=4" encoded files (i have a lot) never go above a certain bitrate supported by my player, i don't need to re-encode them with Divx6.2 ?

thanks
nalooti

[Awatef]

check, you probably forgot that DivX has a built-in resizer.

Well, performance-wise, using the DivX resizer will spare you time, since you will be able to encode in "Fast Recompress" mode. This can save you about 30% encoding time :)
If you are constrained to use "Full Processing Mode" because you have to use other filters, you can still save about 20% encoding time :)
I personally cannot see any difference in quality between the Vdub resizer and the DivX one.

As for the compatibility, I may add that as long as you're using the "Home Theater" profile, you don't have to worry about the version you're using, it will work on any certified device ;)

[nalooti]

check, you probably forgot that DivX has a built-in resizer.

Well, performance-wise, using the DivX resizer will spare you time, since you will be able to encode in "Fast Recompress" mode. This can save you about 30% encoding time :)
If you are constrained to use "Full Processing Mode" because you have to use other filters, you can still save about 20% encoding time :)

Hi Awatef,

That's very interesting for me since i just started using Vdub and don't know all its capabilities. I always used "full processing" mode without doing anything else: just compress video in Divx and audio in mp3 and never using any filter. You seem to say that in my case i can use "Fast Recompress" mode in Vdub saving 30% encoding time while getting the same quality. Is it right ? Can you please elaborate and/or point me to guides describing the differences between these processing mode in Vdub ?

thanks very much
nalooti

[Awatef]

Yes, as long as you don't use any other filters, you better use "Fast recompress". This will avoid color space conversions and speed up the process significantly.

Else, you have to use "Full processing mode" to be able to use the filters you may need, like subtitle filters or noise reduction ones.

"Normal recompress" is different from "Fast recompress" in that it allows you to change the color spaces for the input and/or the output. I actually don't see any application for this, so I never use it.

The "Direct stream copy" mode is useful for example for trimming, or if you want to change the audio format without touching the video, etc

[UFOxyz]

In my experience, this is what i found,
My source of DVD is mostly from recoreded TV or VHS.

Do not use DivX's built-in resizer, it is not good. Even and odd lines don't seem to match well, compared to MPEG mediator.

I'd much rather for DivX codec to send original resolution and pure Interlaced to MPEG mediator. MPEG mediator can do it better.

[Awatef]

@ufo
It's a bad idea to resize interlaced content vertically anyway.
If you have to resize it vertically, then deinterlace first, using a proper deinterlacing filter.

[manono]

Or best of all, frameserve using an AviSynth script, where interlaced resizing and filtering is much easier, and other filtering is as good or better than VDub's, and you can also use Fast Recompress for the speed and quality gains.

I don't know anything about MPEG Mediator.