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View Full Version : DRF analyzer screws up with S/B frames


yaz
5th March 2004, 13:05
afais, lot of pp use this cute little stuff. at the moment i'm not aware of any other way to have a look inside devapi4 xvids. i haven't got any problem with it ... so far.
having analyzed my last encodes i found sg strange. when more than 1 conseq b-frame is set together with gmc (s-frames) drfa reports some occasional jerks in drf usage. it states that time to time quants jump up to 31 producing a small bounch of such frames & then everything goes as expected. the percentage of such frames for a whole film is far below 1%. meanwhile, the average quantizer for the film seems to be ok.
when analyzed with ffdshow, no such qaunt jerks was found.
when quants were restricted (i never do, anyway) the results were the same.
when only 1 conseq b-frame's allowed or when gmc's off, no jerk anywhere. that's why i think that b & s-frames together(!) cause this.
yesterday night i went on a frame by frame exam & i found that the first occurances of these scrambles (i went through only on some of them) were sw round where some conseq i-frames(!?!?) were also present. so ... i'm completely confused now. can anyone explain me this ?

some quests just occured to me about it.
- how safe & reliable is gmc now. i know, i know ... it is(!:-) but anyway. what risk should i take into account (if any) ?
- how safe & reliable is using B & S frames together ? so far i've encoded 8 movies with this settings & i found that b & s frames take more than 60% of all but st it goes far above 70%!

sg ot.
yesterday night i tried the 03040900 build from gam3r & all of my encodes mentioned earlier happened to be decoded as a crap. i've seen from the logbook that sg's been changed in the 'gmc/motion' part. is there sg about to change in it essentially ? if yes, what ? (with older builds decoding seems to be ok)

thx
y

CruNcher
5th March 2004, 13:20
yep you're right latest fix should fix the DivX GMC decoding problems but now we have XviD decoding ones damn :( you have the same problem that black slime is appearing in your video ?

yaz
5th March 2004, 13:34
Originally posted by CruNcher
... you have the same problem that black slime is appearing in your video ? yes. all s-frames seem like shit :-((( some blocks seem to be left undecoded (all pure black) others seem to be misplaced as they were torn a way.
sad sad sad
y

sysKin
5th March 2004, 13:52
OKay confirmed, GMC is broken. @everyone: don't use it in this Gamer's build! I mean don't encode with it, 'cause you'll get problems in the future.

If in doubt, double-check your video with ffdshow, which is probably always right.

@yaz: as for DRFanalyzer - if ffdshow says one thing and xvid's "show me internals" also tells you this thing, they're probably right ;) GMC+bframes are safe to use in RC3.

Radek

CruNcher
5th March 2004, 14:09
yaz about that 31q spike thing yep it looks like DRFanalyzer missinterpreting something here there is actually no spike that goes that high but DRFanalyzer shows it.

yaz
5th March 2004, 16:07
@all
thx guys a lot ! i was about to fall into complete dispear cus i thought i had to reencode all my later stuffs. i try to get closer to this drfa misery at the weekend.
thx
y

CruNcher
6th March 2004, 12:40
yaz the GMC problem should be fixed now :)

yaz
8th March 2004, 09:41
Originally posted by CruNcher
yaz the GMC problem should be fixed now :)
thx, thx, many thx ! :-))) back to xvid again.
i got anything new on drfa. (amof, i was playing with ffvfw at the weekend. shame on me :-)
btw, what's this "show me internals" business ? (maybe, i missed sg)
thx
y