Crap Quality with XVID?

[Murdock0815]

Hey people

Since I just bought a DIVX standalone, I got into DiVY encoding a little bit. I tried encoding Band of Brothers several times, but I keep getting crap picture quality when theres explosions/action happening. I mean, even a VCD would look better.

I meant to put 3 episoded on 1 DVDr. One episode is only like 60 mins, so that shouldnt have been a problem...

1 main movie (about 60 mins), target size at 1450 MB + 1 ac3 sound file. Bitrate is approx 2800. Resolution set to 704x384, VHQ 4, motion search precision: 6, h.263, max i frame 300, min i frame 5, b frames disabled, chroma motion on. second pass same, except not h.263 but modulated.

QPel and gmc not interesting, cause I need MPEG4 compliance for my standalone.

The resulting picture looks fine, but especially explosions looks pixelated and dull.

Any ideas what I could have done wrong?
Thanks in advance

[len0x]

Without results of comp test it's hard to say what quality you gonna get. You might want to try AutoGK to see what kind of quality you can get out of that source.

[manono]

Hi-

Those things are real hard to compress, because of that Saving Private Ryan-like noise they added to it. I'd suggest lowering the resolution. And as len0x suggests, run a compression test so you'll know beforehand what kind of final quality you'll get.

except not h.263 but modulated.

There's a chance that may have something to do with it. It doesn't comply with MPEG4 specs, and may be giving your player fits. Does it look the same when played on your computer monitor decoding with Nic's decoder or with ffdshow? I'd suggest doing both passes with either the H.263 or MPEG Matrix.

[bond]

Originally posted by Murdock0815
h.263 ... second pass same, except not h.263 but modulated.use mpeg in both passes

QPel and gmc not interesting, cause I need MPEG4 compliance for my standalone.qpel and gmc are mpeg-4 compliant its just that first generation standalones dont support it
qpel leads to much more sharpness btw also using a sharp resize filter like lanczosresize

The resulting picture looks fine, but especially explosions looks pixelated and dull.if the source is noisy you can also use some sort of noise filters in avisynth
you can also try a motion dependant filter like QMF (search in the avisynth forum for that) which can use filters only in high motion scenes if specified so...

but all in all its strange that such a high bitrate produces problems, also do a compressiblity test as lenox suggested and report the findings)

[Murdock0815]

Thanks for the quick reply guys.

I should have mentioned that I used Lanzcos as well.

I ll give a compressibility test a shot and try out a de-noise filter (QMF)- as I just didnt expect the picture to be so bad with such a hight bitrate.

With qpel, lets see if my standalone works with it.. :)
Wasnt there a problem with the filesizes variing a lot while using it?

[bond]

Originally posted by Murdock0815
Wasnt there a problem with the filesizes variing a lot while using it?no

[Murdock0815]

Originally posted by bond
no

Heh, ok :)

Until I get finished with my results, is there an approximate rule that I could go by while encoding action (war) flicks? Like a certain de-noise filter?
Since I cant exactly tell which scenes a movie contains before watching it.

[Murdock0815]

Well, I did it.

Thanks to your hints, I encoded a few flicks with qpel, mpeg only "sharper" (no h263) and *drumroll* QMF- with very nice results, even at lower bitrates (~1600) than mentioned before.

Even though it took me a while on how to get QMF working, its proven to be worth the time.

Thanks!