Quality mode in new xvid build?

[Bear]

Hello all,

Those old xvid builds used to have 1 pass quality mode to do the encoding. I found it's pretty easy to use and very useful for my situation.

I just installed the xvid rc1, but there is no quality mode any more.

Does anybody know how I can I use zone setting or some other settings to archive the same result as quality mode does?

Thanks a lot.

[Ark]

you can use 1-pass quantizer mode instead.

Think of:

100% quality = quantizer 1
0%(or whatever the lowest value was) = quantizer 31

This should solve your problem, it's only to get used to this system

I hope this can help you!

[crusty]

Basically quantizer and quality mode have been merged because they're just two different ways of saying the same thing. Except that in earlier versions you could not choose a quantizer of 4.5 in quality mode. So it really makes little sense to have a quality mode.
And people don't have to learn all about quantizers because it is explained in the interface allready. (big file/high quality vs small file/low quality).

[Bear]

Thanks a lot. I got it.

I usually set my quantizer to 4. This number works very well on those low motion scenes. But when it come to high motion scenes, I notice the picture quality are getting worse. Is there any method I can improve the picture quality in high motion scenes?

[Ark]

Originally posted by Bear
Thanks a lot. I got it.

I usually set my quantizer to 4. This number works very well on those low motion scenes. But when it come to high motion scenes, I notice the picture quality are getting worse. Is there any method I can improve the picture quality in high motion scenes?

The only method to improve high-motion scenes quality in quantizer mode is to use a lower quantizer :) ...

...or to use higher motion search, VHQ, and B-vops, and a more "compressive" matrix like HVS_good or H263...






....OR... use 2-pass mode! ;)

[Nazgul]

Originally posted by Ark
you can use 1-pass quantizer mode instead.

Think of:

100% quality = quantizer 1
0%(or whatever the lowest value was) = quantizer 31


Although if you want to think in terms of tradition, 100% is often compared with a quantizer of 2. That's how it was with Divx5, although at one point the might've changed it, I can't remember what they use now.

[Bear]

Thanks a lot.

In the zone setting, I am need necessary to set the weight to 1?

[RadicalEd]

Originally posted by Nazgul
Although if you want to think in terms of tradition, 100% is often compared with a quantizer of 2. That's how it was with Divx5, although at one point the might've changed it, I can't remember what they use now.

DivX 5.11 uses a simple scale of 1(100%) - 31(0%) for quality encoding, dunno about previous versions.

[Q-W-Y]

Dont use zone-quantizer !
Use Single Pass - This is quality mode.

[Bear]

Why don't use zone-quantizer?

When there is nothing in the zone, I notice all the video data are encoded to quantizer 4(constant). But if I set zone weight to 1, some video data move to different quantizers(variables).

[Ark]

Originally posted by Bear
Why don't use zone-quantizer?

When there is nothing in the zone, I notice all the video data are encoded to quantizer 4(constant). But if I set zone weight to 1, some video data move to different quantizers(variables).

Theorically, I think that every encode has a "zone" activated, in fact if you hit "load defaults" there's always a zone active, that starts at frame 0 with Weight of 1, so the codec doesn't scale the bitrate lower or higher, because multiplying it by the weight value of 1 return the same value.
This allows the use of "chroma optimizer" for the entire encode.

These are only my ideas, I may be wrong (probably :))

I haven't tried an encode with nothing in a zone, so i can't tell why this happen... :(

[Bear]

Actually, I not pretty sure what does zone mean. If I set it start from 0 frame and use 1 as the weight. How this setting affect the quantizer?

Or if I set quantizer to 4, and then in the zone, I set start from 0 frame and quantizer to 8, xvid will take which quantizer?

[Soulhunter]

Originally posted by Bear
Actually, I not pretty sure what does zone mean...
Hint... (http://forum.doom9.org/showthread.php?s=&threadid=66206) ;)

Bye

[sysKin]

Quantizer mode in the gui is a convinient workaround which creates quant zones automatically. In the ancient times o beta-3 and before, you had to use CBR and create quant zones, which was pretty confusing and took some time.

This mode turns every weight zone into quant zone using the following formula:
zone_quant = user's_quant / zone_weight

..and keeps quant zones intact, so any user-defined quant zones take priority.

Also, if you don't have any zones or first zone doesn't start at frame 0, a zone starting at frame 0 is added.

:)

[Bear]

Thanks a lot.

Does user's_quant = target quantizer(not the one in the zone)? Is that what you mean?

There is still a question for me. If I have the following setting:

target quantizer = 4

In zone:

Frame # | Weight ( Q ) | Modifiers
0 | 1.00 |
2000 | Q 8 |

Since I have target quantizer set to 4 and I also set quantizer to 8 in the zone after 2000 frames. So after 2000 frames, will xvid take quantizer 4 or 8?