NVOP, what is it and how do I turn it off?

[Gawwad]

actualy i am not too sure
i just compared 2 xvid videos that i had with my stand alone divx player
and i noticed (according to gspot) that the one with nvop had a poor frame rate playback, while the one without nvop played smoothly
plus from googling i found this thread and this one:
http://forums.afterdawn.com/thread_view.cfm/165637philips%20dvp642%20xvid%20re-encode%20settings

so it seemed to me that it is bcz this nvop thing
but anywayz how can i disable this packed bitstream thing from the xvid settings?

and actualy guyz hav u tried staxrip?
http://www.planetdvb.net/staxrip/
its free, and there is no installation
its just a zip folder that u extract and u use the programs within the folder
i am using the default xvid settings for staxrip
so why don't u guyz check out the settings ur self and see why does it produce poor frame rate playback on Philips DVP5100 divx player
i will be realy gratefull if u do that :p

thanx in advance
:thanks:

[bond]

what the guy in this thread you linked to talked about were the fake n-vops created by packed bitstream

obviously they wont be there if packed bitstream is disabled

[Gawwad]

what the guy in this thread you linked to talked about were the fake n-vops created by packed bitstream

obviously they wont be there if packed bitstream is disabled

i see
so its probably bcz of the packed bitstream thing, i get poor frame rate playback

so plz man, can u just check the xvid settings of staxrip from here:
http://www.planetdvb.net/staxrip/download.htm

and tell me what option do i hav to change in order to avoid the poor playback plm

plz plz plz http://img146.imageshack.us/img146/689/140gw.gif

[Elias]

Damn packed bitstream to hell :)

[foxyshadis]

There's something called mpeg4modifier (http://www.moitah.net/) that can undo packed bitstream on already-encoded files.

[squid_80]

This is what I suspected, and wanted to just turn it off. I don't need NVops to improve the quality in my encodes, I just raise the bitrate.
P-VOPS are transformed into N-VOPS (real ones) when the percentage of not coded macroblocks is less than the frame drop ratio expressed as a percentage of the total macroblocks. i.e if the frame drop ratio is 0, all macroblocks must not coded to result in a N-VOP. This means the decompressed frame would look exactly the same as the reference frame. Throwing a higher bitrate at it probably results in lower quantizers, hence more detail is preserved and macroblocks are coded instead of being skipped.
A solution to disabling them completely would be to specify a negative value for the frame drop ratio but sanity checks in xvidcore don't allow for this. This makes sense since as I said the decompressed frame looks exactly the same as the reference frame, it just takes up more space than if it were stored as a N-VOP.

[sysKin]

P-VOPS are transformed into N-VOPS (real ones) when the percentage of not coded macroblocks is less than the frame drop ratio expressed as a percentage of the total macroblocks. i.e if the frame drop ratio is 0, all macroblocks must not coded to result in a N-VOP.

Exactly, this is how it works. If all macroblocks are not coded then coding entire frame as an N-VOP is simply a bitstream optimization, not changing the picture at all but saving some bits.

I suppose you could set drop ratio to -1 if you disagree (API allows that, dunno about GUIs and CLIs).

[Gawwad]

thanx alot foxyshadis for that program
that was exactly what i was looking for

and yes i realized that it is actualy a "packed stream" plm
bcz every video that i had that hav nvop, have packed stream thing
and every video that i had that doesn't have nvop, doesn't hav packed stream thing
so i guess it is just that my divx player doesn't support packed stream videos

from googling, i found this useful link:
http://www.mpeg-playcenter.com/modules.php?name=Forums&file=viewtopic&t=3230
http://www.slo-tech.com/script/forum/izpisitemo.php?threadID=142847&mesto=konec

it says: "If in the Gsopt you see the NVOP highlighted, then movie is encoded with packed bitstream.
and the playback on the player will be jerky."
that is exaclty what i have

thanx alot squid_80 and sysKin for the explanation :)

so just a question guyz
to avoid encoding with packed stream
do i hav to just uncheck the "packed bitstream" box?

http://img48.imageshack.us/img48/2821/16oj.jpg
http://img232.imageshack.us/img232/5575/23iv.jpg
http://img232.imageshack.us/img232/8486/34qi.jpg

right?

[squid_80]

I suppose you could set drop ratio to -1 if you disagree (API allows that, dunno about GUIs and CLIs).The API might appear to allow it but xvidcore uses max(0, frame_drop_ratio) when creating the encoder.

I don't have a problem with them except sometimes S-VOPs get transformed into N-VOPs, which doesn't really work. So I patched my source to check (current->coding_type == P_VOP) before dropping the frame.

[Shinigami-Sama]

o.O S-vop?
and to think I know I knew all the common frame type o.O

[celtic_druid]

GMC. I would imagine that a lot of people don't use GMC anyway since no current hardware can handle 3 warp points.

[Shinigami-Sama]

ah...
ok that makes sense

[Lolitka]

So is there any way to encode withouth n-vops with mencoder (xvidcore, libavc) to avi?

[celtic_druid]

Well, with Xvid, you would just to the same; modify libxvidcore to accept -1, then mencoder to use -1 instead of 0. lavc, I have no idea. Don't even know if it uses N-VOP's at all.

Of course with mencoder, it might drop the frames itself before they even get to Xvid if you don't use -vf harddup, etc.

[Lolitka]

i tryed -vf harddup, but no effect ):

I'm not good in compiling xvid so i will try it with xvid as it is in mencoder (win32).

[celtic_druid]

Well -vf harddup just makes mencoder resubmit dropped frames. Xvid will still drop them if it detects them 100% identical. What I was trying to say is that if mencoder has already dropped a frame, then Xvid wouldn't need to encode an N-VOP.

As it is Xvid will always drop frames if they are 100% identical. Nothing you can do about it without modifying the code. Make more sense to fix any broken decoders that can't handle N-VOP's.

If you use my MTK build with a HT profile, then N-VOP's are disabled. Other than that Xvid will encode N-VOP's if it feels the need to. Although from recollection with older builds, you couldn't have N-VOP's and B-VOP's, so enabling bframes would stop it from producing N-VOP's.

I could probably modify mencoder, but I did some builds only a day or so ago, so it wouldn't be for a while.

[Lolitka]

Well i need it for mp3 player and it needs max b frames 0 and can't paly nvops \:.

So mencoder with patched xvidcore would be realy nice. :)