Illegal GOP question (feature req.)

[krbo]

mainly for jdobbs

Would it be a big problem for you to add a switch like "ignore illegal GOP size" ??

I'm working a lot with DVB-S captures and have a lot of problems with
DVD-RB "illegal GOP size" detection in prepare phase.

Yes, there are everything in those streams, GOPs from 1 to 54 frames, hybrid video but I would like to have opportunity to feed that stream to encoder via DVD-RB.

btw. I'm from PAL side of the world

[jdobbs]

Hmmm.... I guess no matter what you select it always needs to be bigger. I think I have the maximum GOP size that DVD-RB will accept as input set to 50... I thought that would never happen unless something is definitely wrong. I'll change it to 60...

[laserfan]

krbo you might also try running your captures thru VideoReDo Plus, which can re-construct long Gops to a (standard) length of your choosing. In addition it's a killer frame-accurate editor.

[krbo]

Hmmm.... I guess no matter what you select it always needs to be bigger. I think I have the maximum GOP size that DVD-RB will accept as input set to 50... I thought that would never happen unless something is definitely wrong. I'll change it to 60...

it's certainly wrong for a DVD , but long GOPs are not rare for DVB broadcasters
,helps those limited with transponder bitrate to have more compression on a lot of P&B frames.

(usually it's a syndrom of badly set up statistical multiplexer)

(btw. sometimes ProjectX reports of 3 fields GOPs after demux - what the heck is that, 1.5 frame GOP?)

[krbo]

krbo you might also try running your captures thru VideoReDo Plus, which can re-construct long Gops to a (standard) length of your choosing. In addition it's a killer frame-accurate editor.

yes, I heard that. Also mpeg-vcr is able to fix GOPs but that solution somehow stinks for me. Messing with GOPs without recoding, hmmmm

I'd rather let the encoder to fix that problem (for me the only reason of reencoding DVB captures is filtering video, it's rare to have material bigger
then DVD-5)

It's so easy to become lazy with jdobbs' nice product, just a few clicks and
a lot of free time :)

But certainly will test VideoReDo, thanks for mentioning.

regards,

[jdobbs]

it's certainly wrong for a DVD , but long GOPs are not rare for DVB broadcasters
,helps those limited with transponder bitrate to have more compression on a lot of P&B frames.

(usually it's a syndrom of badly set up statistical multiplexer)

(btw. sometimes ProjectX reports of 3 fields GOPs after demux - what the heck is that, 1.5 frame GOP?)It probably has 1 frame and it has the RFF flag set.

[Trahald]

videoredo does reencode but just minimally.. wherever there is a long gop it just encodes the excess for just that gop into dvd spec duration(s).