audio interleave

[Zhnujm]

is it possible or will it be possible some time to use interleave in ms instead of frames ?
i have to use 96ms for perfect ac3 playback, 1-3 frames dont work. :(

[The FX Files]

Really? I never heard of that... Is that something to do with Dolby decode buffering?!?! Please tell me more :)

[Snike42]

I love the way GKnot does almost everything for you and ends up with a complete movie ready to use. But for ac3 I mux manually to get 64 or 96 ms interleave.

Would be very nice if GKnot also could mux in ms!

Snike

[3D]

Yes, yes, yes... Sometimes if you do not use a 64 or 96ms the playback will studder, not on all movies but some... I do not mind muxing manually it only take 5 min at most, just would be a nice feature...

[MaTTeR]

Originally posted by 3D
Yes, yes, yes... Sometimes if you do not use a 64 or 96ms the playback will studder, not on all movies but some... I do not mind muxing manually it only take 5 min at most, just would be a nice feature...

I'm not disputing this claim but after close to encoding 30-40 movies with the AC3 track and using the default (500/1) interleave settings, I've yet to see any playback problems. Maybe I've just been lucky but I found that the sound starts getting screwy if I mess with the interleave settings.

[mwillberg]

I also get jerky playback if I use "Interleave every frame", and instead I use "Every 96ms". I believe this is what Doom9 uses in his guide as well. However, I don't think anyone does a 1CD-ac3-movie, and then it doesn't matter how GKnot muxes the first version. Just use the correct setting when you split your movie to several CDs.

[nepuko]

I'm not disputing this claim but after close to encoding 30-40 movies with the AC3 track and using the default (500/1) interleave settings, I've yet to see any playback problems.

I don't know how you do that Matter. May be you just don't use SB live sound card. We had in the past a big discusion (sorry cant find it now) in Audio forum about interleaving values for Avi-AC3. After thorough testing we found, that the best values are 64 or 96 ms and I think that was the reason Doom9 has updated the guide. I personaly use 64ms, any other value - 120, 100,90, 70!!,60!!, 50 except 96 gives me a stuttering video. Someone explained that with the nature of SB live buffers. I hope the guys with Yamaha cards don't have that problem otherwise they have to search their own values.
I'm doing also manual mixing with Nandub, because of Gnot's mixing values.

[MaTTeR]

Originally posted by nepuko


I don't know how you do that Matter. May be you just don't use SB live sound card.

That's exactly right ;) I had way to many driver/software issues with it not to mention the various SPDIF rants which I won't go into. I bought a Zoltrix Nightingale 5.1 Pro card and haven't looked back since. It's been well worth the $49 I paid. No driver or SPDIF issues anymore and the sound quality is better than Live IMO.

PS. I've been using both Gknot and NanDub to mux the AC3 tracks and both work out perfectly so far. Knock on wood:D

[Snike42]

I don't think it's sb-live related. I have a Terratec six-pack sound card with s/pdif output and my video also stutters when i use 1/2/3 frame interleaving.

I read somewhere that every AC3 frame holds 32ms of audio. So maybe the interleave has to be a multiple of 32 ms?

Snike

[CdinT]

I also use for ac3 64ms but with 250ms preload. With 500ms preload it didn't work good (jerky pans and zooms).

[pdontthink]

Dunno if this is the right thread for this, but
it seems you are the folks to ask:

I just did a first try at encoding with GK, DivX4.12
and two AC3 tracks ("Just MUX").

Everything seemed to go great, the final file size
appears to indicate that the audio is there, but I
cannot hear it in any of my players.

I *can* play the raw AC3 files in my player, but no
sound in my final AVI.

Suggestions?

Thanks!

[TheWEF]

the audio-data has to be put in between 2 frames, it can't be put in the middle of a frame.

so it depends on framerate what ms-values are possible.

e.g.:

pal 25 fps
1 frame every 40ms.
so 40, 80, 120,... is possible. = 1,2,3 frames.

forget these ms-values!

wef.

[Zhnujm]

i also cant see a way to put audio in a frame, but why the hell does it play smooth with 96ms and not with 40,80,120 ??

if you make a test you will see that the filesize for 80,96,120ms is not the same so there must be a difference.

[CdinT]

That is my case too, TheWEF. I don't no why but my movies doesn't play smooth at 40, 80 and it does perfectly at 64 and a preload of 250ms. And it's 25 PAL.
I got a old (first model) Soundblaster Live Value.

[TheWEF]

i'm not sure, but maybe if you enter 60 you get alternating 40 and 80...
please post the number of frames and the difference in filesize when muxing with 40 and 60.

wef.

[Zhnujm]

maybe i found some info:

in the properties of the "default direct sound device" or the "waveout device" there is a buffer info. if you interleave at 64 or 96 it stays constant at 64/96ms. if you use another value the buffer is not constant and changes between 32/64 or 64/96. seems the buffer can only be changed in 32ms steps. maybe the switching of the buffer size causes the stuttering.

just tried 128ms interleave and it works the same.

[Jbrohms]

to the people with problems. What kind of hardware are you using for playback?

I read somewhere that you need at least a 500mhz processor to play back AC3 from cdrom.

Please let me know. I get the sme problem with sound blaster