Non standard GOP length

[screen54]

Just wondering what people think.

More and more DVB-S broadcasts in Europe are showing up with a GOP length of more than 15. If a DVD is made from these video files without any alterations, the resulting disc will not be strictly PAL standard. TMPEG DVD Author will alter the GOP length to give a compliant DVD. IFOEdit will happily bump out a disc without these alterations.

Both play fine on most DVD players and in truth, I can't see any difference.

Is altering the GOP length considered re-encoding or is it just like resetting the header flags? Do we make compliant discs or not?

Thoughts and advice appreciated.

Cheers,
G.

[AAR.oner]

no, altering GOPs is not re-encoding

[screen54]

Thank you for the reassurance. Compliant discs it is then :D

[DanielG]

no, altering GOPs is not re-encoding

Are you sure? This thread over at Doom9 suggests that altering the GOP requires a re-encode.
http://forum.doom9.org/showthread.php?p=1336483

[AAR.oner]

no, i ain't 100% positive since i've never needed to alter GOPs...i know i've *heard* there are ways to go about it without re-encoding the whole stream...i believe DVDSP will do it, but again i've never needed to so........i could be wrong on this one

i'm sure he/she can research a bit and figure out how exactly



personally i would leave it as is...just my .02

[Thulani]

TMPGENC has that feature which shows which frames are re-encoded. Every time I tried to do some menus with it on a show with non-standard GOPs it shows that re-encodes the files. But after watching the resulting files I don't see any difference in quality.