2 pass broken... bitrate of resulting file is way off (like over 2300 megs)

[morello12]

Hmmm... I don't know what to post for info but basically I'm trying to encode a 1:40 hr clip at around 2.1 gigs. Everything seemed to be working fine, until I raised the bitrate to 2.8 gigs, then I started getting incredibly compressed small files, like around 1-600 megs for the entire movie. 4.8 gigs made the same results, around 600 megs even though I tell it 5,000,000 Kbytes.

Is this normal? All my encodes made for 3 cds or less seem to work fine, but raising the bar seems to have strange effects. In the quality based mode, I can easily encode the project to around 4+ gigs just by setting to 99%. 100% would probably drive it over 6-8 gigs. So what's with the 2.1 gig limit in the 2 pass mode?

Anything I've overlooked?

Thanks.

[-h]

Hm interesting.. I'll have to ask Foxer about it, as all size-sensitive calculations use either __int64 or double variables which are good up to ludicrous sizes.

That aside... I'm not sure that 2-pass is what you're after. How large is the 1st pass file? If it's near or below the size you're after, I'd just use it instead of a second pass, as the quality will only get worse if you perform a 2nd pass (quant=1 is buggy, and completely pointless in MPEG4 anyway).

-h

[rui]

Originally posted by -h
That aside... I'm not sure that 2-pass is what you're after. How large is the 1st pass file? If it's near or below the size you're after, I'd just use it instead of a second pass, as the quality will only get worse if you perform a 2nd pass (quant=1 is buggy, and completely pointless in MPEG4 anyway).

-h

Is this the reason that made Doom9 recomend in his xvid guide to use quantizer limit 2-31 instead of the default 1-31?

[wing1]

@morello12

I am experiencing the same phenomenom using 1-Pass(CBR); However, this is a blessing rather a problem. The higher the value I raised the better the quality (less macroblock and sharper picture) until a peak point is reached and then the quality droped drastically: The file size and the data rate went the opposite ( decrease ). However, the latest CVS build just do the opposite and no matter how small the bitrate you set, the data rate keeps on climbing. I can easily make a 15min clip to be 2Gig in size :D

[-h]

CBR mode is horribly broken at the moment (and has been ever since the new core was added), I would avoid it at all costs.

Foxer is thinking of looking at a replacement.

-h

[morello12]

I think i've figured out the problem. Apparently if you make the bitrate in the 2pass mode larger than the biggest possible file you can get (from 1 pass quality based), it just for some reason defaults to using the least amount of compression possible, or cause some other strange errors.

I would think the best way to handle this situation is to show the user what the highest possible bitrate is they can use (obviously the codec knows somehow), and if what they enter is over that, just substitute the highest properly working bitrate in for the encode and inform them that the file cannot be compress to that large.

Thanks for the help and responses