asynchron audio in MP4. How to correct audio offset?

[hk]

Hi,
I got
-an audio AACfile with a -280msecs offset (value given by DVD2avi)
-an MP4 file (created with mpeg4creator)

If I mux the two in mpeg4creator60 or in mp4ui they are of course asynchron. How do i deal with audiooffsets when creating ISO compliant MP4 files?
Any help is appreciated, greetings from
HKA

[Kyo]

If you make your AAC with AC3machine just be sure to check if the checkbox "Set delay to" is active and the value is -280 with this your AAC will be offset in such way.

[hk]

Hi Kyo,
well fine, I did this. But the problem is, that eventually, when I mux the aac with the mp4, I have to consider this value (eg-280)!
Like muxing in NanDub a MP3File with the corresponding divx.avi, I also
have to set the audio delay to -280.
And it´s this feature I miss when muxing aac and mp4 with mpeg4creator or mp4ui.

Or am I totally aside my shoes?
Greeting HkA

[Kyo]

Put again your shoes :D

Nop and Yes, well if you HAVE set the delay in AACMachine you don't HAVE to set it again in other option (even in nandub) doing this you apply 2 times the delay. But if you AAC + avi is async other will be the problem
like the player, what player you use?

[hk]

Hi Kyo,
You are probably right, although the Divx guides in doom9 tell you to set the audiodelay in nanDub accordingly the value DVD2avi gave you first. And somehow, this makes sense!
As a player I use tthe envivioTV 1.2 plugin with Quicktime or WinMediaPlayer 6.4. It´s asynchron in both.

So far I put on one shoe..and smile,
Yours HKA

[Kyo]

Hehe :)

Well i think that you spoke about the nandub guides to mux ac3, before Ac3machine(or BeSweet, AACmachine, OggMachine... Thankyou DSPGuru) there is not other way to put a delay in an ac3 streams or mp3 or ogg or aac, thus we set the delay in Nandub, but now thanks to DSPguru programs we set the delay in his programs.

I hope I had explain you better why no set again the delay in Nandub.
:o


Cheers.

[DSPguru]

issue is also covered in the faq (http://forum.doom9.org/showthread.php?s=&threadid=15738) :

20. the BeSweet guide says that you should set an audio delay, But later in Nandub/GKnot, you should enter the delay value from your AC3/MP3 file in the delay audio track by XY ms field :confused:
you should compensate for the delay only once. either with BeSweet or with Nandub. one should be the A/V delay, and the other equals to zero.



@Kyo
10x :).

[hk]

Ok, understood...
I so far assumed that "delay" is a non destructive value, so that I would have to set it in every step of the process.
But if it´s destructive, it makes things much simpler. Many thanks for your advice Kyo and DSPGuru,
and greetings, HK