Interleave Audio

[Justaphase]

this option is on the video editor im using and will can anyone tell what this basically means? is it better to interleave the audio or not? if i do what rate should i set it as like interleave every how many seconds? sorry about all the questions but ive not got a clue about it. thanks

[thecrock]

Interleaving is how audio and video are synchronised in one file for playback, whenever i open an avi in virtualdubmod it tells me that the movie is interleaved every one frame, so i would set my video editor to interleave once every frame. I'm not an expert in this field so i may be wrong.

Anyone?

[somebodeez]

Awhile back, I was very curious about this so I did some searching. I found a webpage that said interleaving AC3 audio was rather like gluing the audio to the video. They had a chart that listed some values and I kept notes. Unfortunately, I haven't been able to locate that webpage now.

AC3 Bitrate      Preload (ms)    Interleave (ms)
       448               128                  128
       384               160                  160
       256                48                   48
       224                64                   64
       192                80                   80

Since then, I've been using those values and they seem to work for me. The AC3 audio plays back in sync with my video on my Philips 642 set top player. I don't know how the values are figured - again, this is just a note that I took from that website.

I've noticed that generally, after interleaving AC3 audio, my files are 1 mb less in size.
Hopefully, someone here can shed some light on this for us.

[FulciLives]

@somebodeez

What program are you using to do the muxing or interleaving?

I am guessing either VirtualDubMod or Nandub. Maybe somethig else? Also what version of the program are you using?

I just got a Philips DVP-642 to "play" around with and I must admit that Xvid videos from a DVD look damn nice on it.

BTW I've just been keeping it simple (so far) and using AutoGK with both the ESS option and bitrate spike option enabled.

The few Xvid DVD backups I have made seem A-OK (upon playback on the Philips DVP-642) but I found another cuirous thing.

According to a post I found (can't find it now) you will lose audio sync on playback whenever the Philips DVP-642 hits an "N-VOP" frame.

You can load your Xvid into MPEG-4 MODIFER and it will tell you if you have any N-VOP frames and if so how many.

So far of the 5 DVD movies I have backed up ... all using the same options in AutoGK ... only 2 have shown "0" N-VOP frames. The other 3 have 1 or 2 each.

The one movie must have one very early on because the sync is off until I rewind and play (only have to rewind for like a second). Then the sync is ok.

But I find that very troublesome. What is an N-VOP frame and how can you encode to prevent it?

Also is this an Xvid only thing or does it happen to DivX as well.

Perhaps I've taken this thread of course but the whole idea of Interleave is to "get it right" so it plays back "correctly" and since the Philips DVP-642 is the most popular stand alone DivX player ... it makes sense to me to bring this N-VOP frame thing up now.

- John "FulciLives" Coleman

[somebodeez]

@somebodeez

What program are you using to do the muxing or interleaving?

I am guessing either VirtualDubMod or Nandub. Maybe somethig else? Also what version of the program are you using?

What is an N-VOP frame and how can you encode to prevent it?

Also is this an Xvid only thing or does it happen to DivX as well.

Perhaps I've taken this thread of course but the whole idea of Interleave is to "get it right" so it plays back "correctly" and since the Philips DVP-642 is the most popular stand alone DivX player ... it makes sense to me to bring this N-VOP frame thing up now.

- John "FulciLives" Coleman

I use GKnot, VirtualDubMod 1.5.10 build 2439 and I've been using DivX 5.05 (Home Theater Profile).

Well, just last night for the first time, I had to use the rewind/FF/Play trick on my Philips 642 on one of my DivX AC3 rips even though I have interleaved the audio So apparently, whatever it is can happen with DivX too sometimes.

The same file had no problems whatsoever on my LiteOn 2001 (which hasn't had firmware support in ages now)

This N-VOP frame thing you mentioned - I have no idea but I am interested in the answer

[celtic_druid]

My advice would be for AC3 to use AVIMuxGUI with the AC3 standalone profile and for mp3 use the mp3 standalone profile.

[FulciLives]

Check to see if the "offending" file has N-VOP frames.

You can do that with a program called MPEG4 MODIFIER

Also keep your eye on this thread ---> CLICK HERE

- John "FulciLives" Coleman