Bframe Decoder Lag???

kiarrens · Post by **kiarrens** » Tue Mar 30, 2004 9:26 am

It's me again. Don't know why I'm having so many problems lately...
Alright, so I'm breaking an "AMV rule" and using fansubs - but don't kill me, I used AVS to edit out the subs and it's still great quality footage that's not available over here yet. (Full Metal Alchemist)
So anyways, I noticed that when I wrote the avs, certain ones said this on the screen when I checked them in VDub:
WARNING: NOTHING TO OUTPUT
BFRAME DECODER LAG
But they played fine after that first second or so, so I thought it would be alright to edit with. Keep in mind that only 8 of the 15 files did this... O_o So anyway, I made the AMV in premiere and it worked fine, everything edited nicely, UNTIL I tried to export. On the clips that are from those 'bframe' avs files, it'll only export about 20 frames before Premiere crashes on me. Please tell me there's a way to fix this, as I've put about 12 hours into the video...

PS, here's the avs script. They're all the same except for the destination...
AVISource("D:\Fansub\FMA\Episode_3.avi")
Crop(0,0,0,-80)
Addborders(0,40,0,40)

Zarxrax · Post by **Zarxrax** » Tue Mar 30, 2004 10:05 am

B-frame decoder lag will kill frame accuracy. You aren't supposed to edit with divx/xvid clips.

Zarxrax · Post by **Zarxrax** » Tue Mar 30, 2004 10:11 am

Try converting the avs scripts into huffyuv and replace the clips and see if that helps.

trythil · Post by **trythil** » Tue Mar 30, 2004 11:28 am

Succinctly put, the reason why you're getting that message is because B-frames in AVI containers are hacked.

More specifically: what happens is that if you use B-frames in AVI with XviD or DivX, the codec packs several frames into one frame, and sticks null frames after the "real" frame. The null frames act as commands to remove frames from the packed representation in correct order. Therefore a one-frame lag is necessary in order to get things going, so to speak.

(I think that's right; I could be wrong. If I am, someone like AD or sysKin will probably bitchslap me.)

In any case, Zarxrax is right -- AVI files encoded as such will wreak havoc with editing software. Even if your system was set up in such a way that it COULD handle such files with stability, you won't get frame-accurate cuts unless your software is smart enough to recognize that it needs to index the file before using it for editing, and I've yet to see something that can do that.

kiarrens · Post by **kiarrens** » Tue Mar 30, 2004 12:03 pm

Thank you both so much, I'll definately take that into consideration... The thing that confused me was that only half of the episodes were like that, and I had no trouble whatsoever editing the avs in premiere. It's only the export that's not working. ~_~
I'll try converting the avs scripts into HuffyYUV like you suggested, I hope that works... It won't remove all the clips from the timeline, will it? O_o

Zarxrax · Post by **Zarxrax** » Tue Mar 30, 2004 12:15 pm

Just either use premiere's "replace clips" feature, or change the avisynth scripts to point to the huffyuv files instead of the xvid files.
Before you swap though, MAKE A BACKUP OF YOUR PROJECT. From my experience premiere is fickle about either one of these operations and you could very well lose your work if it doesn't happen to be agreeing with you today.

kiarrens · Post by **kiarrens** » Tue Mar 30, 2004 12:27 pm

Awesome, will do. Thanks for all the great advice, you're both life-savers... or AMV-savers in this case. ^_^

kiarrens · Post by **kiarrens** » Tue Mar 30, 2004 1:22 pm

*sighs, rubs eyes* Any suggestions on converting the files? I tried converting one of the episodes in Vdub and it stopped at 4GB, said it was too big (even without audio). I'm at a loss... Unless you think I should just split the episodes and convert them in pieces, then write avs for each separate piece, which means I'll have to completely re-edit all those scenes since I KNOW premiere won't accept those files in lieu of the old ones.
*Note to self - Bframe decoder lag = 3vil.

VegettoEX · Post by **VegettoEX** » Tue Mar 30, 2004 1:28 pm

kiarrens wrote:*sighs, rubs eyes* Any suggestions on converting the files? I tried converting one of the episodes in Vdub and it stopped at 4GB, said it was too big (even without audio). I'm at a loss... Unless you think I should just split the episodes and convert them in pieces, then write avs for each separate piece, which means I'll have to completely re-edit all those scenes since I KNOW premiere won't accept those files in lieu of the old ones.
*Note to self - Bframe decoder lag = 3vil.

Sounds like you're working on Win 95/98/ME. You're going to have a limit of 4 gigs for any file you create, really; it's just how the file system works (Win2K, XP, Macintosh, etc. don't have this problem).

If you're going to go this route (converting stuff over to Huffy, which does sound like the best option), your best bet is going to be to export <B>just</B> the clips from the episodes that you want to use. Since you've already edited your video, you should have a good idea (more or less) of what scenes you're using, so it shouldn't be all <B>that</B> bad... just more of a time-waste, than anything.

Zarxrax · Post by **Zarxrax** » Tue Mar 30, 2004 1:44 pm

In virtualdub there is an option to split the files as it encodes. I believe this option is on the save as dialogue box. Just split up the huffyuvs like this, then create an avisynth script to simply join them back together like so:
AVISource("part1.avi")+AVISource("part2.avi")+AVISource("part3.avi")