#2 mp4ui doesnt handle b-frame muxing right!


there are two problems when muxing b-frame content in
avi into mp4:

1) "delay frames", caused by the old VFW interface most
codecs still use (XviD, DivX5), which requires 1 frame in
and 1 frame out, which isnt the case with b-frames and
therefore vfw outputs so called delay frames

2) "packed bitstream", a hack caused by the old AVI
container, which is not really capable of storing b-
PB is used in DivX5 and by default in the latest XviD

mp4creator and mp4ui (i assume as its based on it) isnt
able to detect and remove these avi/vfw problems when
muxing b-frame content into mp4, and therefore the
produced mp4 files are heavily borked!

as the mpeg4ip guys doesnt seem to have any interest
in this, imho very important (as as good as all divx5, xvid
encodes use b-frames), issue, i ask you directly to have
a look at this

jeanlf from the gpac project is currently working on
solving these issues with his mp4box (a tool similar to
mp4creator but with bifs encoding) tool, but it doesnt
seem to be 100% stable atm (7th february)

maybe you want to have a look at his code and use it
for muxing avi content in mp4 with mp4ui!


  • Markus Brenner

    Markus Brenner - 2004-02-07

    Logged In: YES

    "no time right now" - see your feature request...

  • bond

    bond - 2004-05-11

    Logged In: YES

    gpacs mp4box avi import code now seems to be rock stable,
    would be great if you could use it instead of the mpeg4ip
    code when importing video streams from avi


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