#192 BitrateRecalculation

closed-invalid
nobody
None
5
2004-08-11
2004-07-28
Anonymous
No

When using multipass (3 or more) divx5 encoding,
probably also when using xvid and divx, gordianknot
skips recalculating the bitrate depending on the size of
the outcomefile. This makes 6-pass encoding pretty
useless...

If you try to hit a AVI of 1400MB and the second pass
hits 1200MB, the third, fourth, fifth and sixth pass will
just be a rerun of the second and also hit 1200MB.

To fix this, you should recalculate the bitrate by:

Easy way:
if result is smaller than wanted size:

third pass bitrate = second pass bitrate * ( wanted
size / resulted size)

But this is better:

3rdpassbitrate = 2ndpassbitrate * ( ( (wanted /
resulted) - 1 ) * 2 + 1 )

if result is bigger than wanted:
4thpassbit = 3rdpassbit * ( 1 - ( ( 1 - ( wanted /
resulted ) ) * 2) )

Regards
A fan of GordianKnot (despite this flaw) ;)

Discussion

  • Tony Lenox
    Tony Lenox
    2004-08-11

    Logged In: YES
    user_id=1165

    the only way second pass would hit 1200Mb is when movie is
    maxed out, so putting more bitrate will NOT help (you will still
    end up with 1200Mb)

     
  • Tony Lenox
    Tony Lenox
    2004-08-11

    • status: open --> closed-invalid