decode audio or not to decode

[DaveQB]

i have always taken the wav file that DVD2AVI creates and used that to make my avi/dixv/mpeg2 etc video file

but reading this here, maybe i have only been lucky with my sync

http://nickyguides.digital-digest.com/DVD2AVI.htm


saying...
"DVD2AVI can do audio decoding but its probably better not to use it because of synch problems."

is it just because i am in a PAL country and therefore have a PAL source VOB ??

seems from looking at this forum many others use DVD2AVI for sudio decoding.

would graphedit create better audio in terms of quality and sync (sync never been an issue before) ???

[hakko504]

First, Nicky's guides are OLD. They haven't been updated in two years time by now and you should cross check everything you read there. They do have a lot of good information, but as you can see from the linked page he refers to VirtualDub 1.4d which is severely outdated by now.

To your question: No, a properly ripped DVD will not give you audiodesynch if you use DVD2AVI. Graphedit is a much worse alternative - harder to use and won't increase neither synch nor quality. Use demux instead and convert the audio with BeSweet instead - that is both faster, less HD consuming and with better quality.

[DaveQB]

demux in DVD2AVI ??

i think i do, i end up with a wave file and i either add that through VD or compress to ogg and add (just trying that and all good so far)

yeah i read that he isnt updating, but it does have lots of useful stuff i cant find anywhere else.


thanx! :)

[cult]

demux not decode,you ll get an ac3 file

[DaveQB]

AHH ohh ok,

so an AC3 file is "is both faster, less HD consuming and with better quality."
to work with then a raw wave ?


hmmm, must try that next time,


thanx guys! :)

[DaveQB]

or demux through DVD Decrypter ??

for that matter demux all relative files, including the video??

experimenting with that now....

potential problems ??
eliminates the DVD2AVI step altogether

i think :D

[wertert]

I have been using demux to d2v+ac3 for a while but dvd2avi seems to drop frames off the start of the movie which affects the a/v sync . See this (http://forum.doom9.org/showthread.php?s=&threadid=44150) thread.

One way round this is to decode to wav with dvd2avi. This gives you a wav file that seems to start after the dropped frames. The ac3 file seems to start from the start of the vob file and doesn't factor in the missing frames ( you also get a DELAY in the filename but this does not cover the missing frames ).

ac3+besweet is a nicer way to go as you have many more options but I really hate lipsync problems. Not that I'm obsessed ......

[DaveQB]

well i am pleased to say that i managed to by pass the DVD2AVI step by using DVD decryptor in IFO mode and demuxing the video and audio streams

from that you get m2v and ac3 files and simply encode them,

just finished up a DVD doing that and all in sync and looking good

any potential problems foreseeable?
this was a DVD ISO if that makes any difference

[wertert]

what do you use to convert the m2v into avi. mpeg2avi ? and do you convert straight to divx/mpeg ?

The only nice thing about dvd2avi was being able to use avisynth+d2v file to address the original vob files without needing a large inter file. Saved lots of disk space.

[DaveQB]

loaded the m2v fle straight into VDMod 1.5.1.1a

and away we go... :D

[wertert]

I think i'll give this a go. I normally use smartripper but i'll download decrypter. Do you run it as 'stream processing' to create a single m2v file ?

also - do you demux out a seperate ac3 file ( with the DELAY in the file name ). If so how do to covert/combine back into the move ?

Thanks for the help

wertert

[DaveQB]

yeah yeah, stream processing,

i got two english audio files out of this dvd, a 2channel one and a 6 channel one.

once the m2v is loaded into VD mod you can do th audio a few different ways.

you can choose the audio stream with VD Mod, it support AC3

then delay it the amount of ms that is in the file name,

or, what i di was encode the audio with GoldWave and encode the Video to Xvid and then mux them with Ogg mux

all depends what kinda audio stream ya want,
i prefer .OGG

easy. :D

[wertert]

given this a go and it seems to work well ( apart from vdubmod crashing right at the end which I encode the sound with mp3 ).

One thing - some of my movies ( galdiator PAL/ pitch black NTSC ) have a audio offset of 0ms. This is what is reported by the ripper/vobedit etc BUT this seems to be the offset of the 'universal' trailer that preceeds the movie. When I mux back in the sound with 0ms offset it's way off. The problem is that trailer is in the same chapter as the start of the movie.

If I use vstrip to check the audio delay in the first vob file ie vstrip.exe C:\gladiator\video_ts/VTS_01_1.VOB iC:\gladiator\video_ts/VTS_01_0.IFO -w1024 . I get a delay of 0ms ( like above ) BUT if I check the delay from LBA 1 ie -w1024 -s1 then I get a delay of (delay -0:00:00.560). So what is going on here ?

wertert

[DaveQB]

hmm, not sure
havent tried your methods there

only used this method of DVD Decrypt once and will try it again and report back...

[wertert]

do you ever get an ac3 stream that has an offset of 0 ?

[DaveQB]

i haven't used AC3 streams much in my time, but i do sometimes have wav files with 0 offset,
rare though, of course

[MasterYoshidino]

The only dvd I touched that had zero ms delay in the AC3 was the Pink Pineapple DVD Soreyuke Marin-chan series. (hentai anime region 2)