[MEncoder-users] level_idc, PS3 DivX implementation and re-encoding

[Alex Bennee]

Hi,

Reading the mailing list[1] I notice a number of people have pointed out
problems getting DivX stuff to play on the PS3. The consensus seems to
be that the PS3 cannot play stuff encoded at the default level_idc
value. I have a number of files I encoded before I used my current
encode profile [2] which therefor don't play on my PS3. From my
cursory reading of the spec [3] it seems that level_idc specifies a
maximum limit for various encoder operations.

Is there any way to check if an encoded file actually exceeded these
limits in it's encoding? If the limits do not exceed that of a lower
level_idc value should it be possible to tweak the file without
re-encoding?

Failing that is it possible to re-encode by only re-coding the blocks
that exceed the lower level_idc limit? Or is a normal re-encode the
only solution (with the attendant losses)?

I've tried to find the header described in [4] just to try hacking the
level_idc in the header to a lower level and seeing how the PS3 copes
with it. However I don't seem to be able to find the referenced
sequence of bytes. This may be because my file is in an AVI container
instead of a .h264 one?


[1]
http://lists.mplayerhq.hu/pipermail/mencoder-users/2008-September/009431.html
[2] -x264encopts
subq=6:bframes=3:partitions=p8x8,b8x8,i4x4:weight_b:threads=auto:nopsnr:nossim:frameref=3:mixed_refs:level_idc=41:direct_pred=auto:trellis=1
[3] ITU-R H.264 Annex A.3
[4] http://lists.mplayerhq.hu/pipermail/mencoder-users/2008-September/009468.html

--
Alex, homepage: http://www.bennee.com/~alex/
CV: http://www.bennee.com/~alex/cv.php