Audio Framerate conversion 23,976 to 25.000

[mcmanuf]

Hi.
I've got a 5.1 ac3 track with the framerate 23,976. Is there any way I can change the framerate without using beswet v 1,4 with the ac3enc.dll file.

The wanted framerate is 25.000

The reason why i dont want to use besweet is because it makes the sound volume low.

Any help is appreciated.

Thx

[bond]

Originally posted by mcmanuf
I've got a 5.1 ac3 track with the framerate 23,976. Is there any way I can change the framerate without using beswet v 1,4 with the ac3enc.dll file. besweet 1.4 is outdated, try the 1.5b versions

The reason why i dont want to use besweet is because it makes the sound volume low.besweet doesnt make the sound lower than it is in the ac3!
you can also try using hybridgain in besweet...

[mcmanuf]

thx for the answer.

I know that v1,4 is outdated, but version 1,5 doesnt support ac3.

And beside ac3enc is known for its low sound issue.

I dont want to use hybridgain because i think its a waste of time.

[KpeX]

The latest beta of besweet has brought back AC3 encoding support.

So let me get this straight...you want higher volume but you refuse to use a method to obtain a higher volume because it's a waste of time.

Audio doesn't have a framerate. If you want to time-stretch the audio to match a video framerate, besweet is your only free choice. Alternatively you could decode to wav with besweet, time stretch with audacity, and reencode to AC3 with a payware encoder.

[Matthew]

I know this is hijacking the thread a little, but is BeSweet's time stretching as good as say Sound Forge's (in the same way that they'd be equal in, say, mp3 decoding)?

[bond]

it was long time said that Prosoniq TimeFactory is the highest quality tool for time conversion (supports pitch correction aso), dunno how besweet handles this now...

[KpeX]

Audacity (the free and Open source audio editor) now supports time stretch with pitch correction. As I have no need for such conversions I haven't tried it yet but I'd recommend giving it a shot to anyone who wants to do a free high quality time stretch operation.

[Matthew]

Well, I wasn't referring to pitch correction or anything like that, merely just the plain vanilla time-stretching/compacting operation. The optimist in me says this would be like decoding mp3 - an automatic operation that should be pretty much a constant unless implemented badly. Then again I have little idea about thse matters :\

Incidentally I remember reading an interview with a guy from Dreamworks regarding the Shrek R4 release, granted it's a little old but he said most studios don't use pitch correction unless the director specifically requests it.

[KpeX]

Originally posted by Matthew
Well, I wasn't referring to pitch correction or anything like that, merely just the plain vanilla time-stretching/compacting operation. The optimist in me says this would be like decoding mp3 - an automatic operation that should be pretty much a constant unless implemented badly. Then again I have little idea about thse matters :\

Incidentally I remember reading an interview with a guy from Dreamworks regarding the Shrek R4 release, granted it's a little old but he said most studios don't use pitch correction unless the director specifically requests it. Huh? If you stretch the audio, the pitch will change, therefore you need pitch correction to retain the original audio. Of course studios don't need it, but they don't do weird things like NTSC to PAL conversions.

I just added some info on this subject to Q19 of the General Audio FAQ (http://forum.doom9.org/showthread.php?s=&threadid=68300#post424063). hth,

[Matthew]

The 24->25 fps that studios do on almost all movie PAL DVDs results in the video and audio being ~4 percent faster. And the audio is certainly not always pitch corrected.

So as far as the audio stretch/compact issue, what the studios do is (almost) akin to a NTSC->PAL conversion.

BTW here's the relevant except from the interview I mentioned:

AK: Was the same audio master used for both the theatrical and DVD releases of the film?

MA: Yes, it is the same 5.1 mix we used for both. The only difference is for the PAL market everything runs at 25 fps so you are going to hear a little bit of pitch adjustment on that.

AK: Is the transfer pitch corrected?

MA: We typically try not to do that only because pitch correction can add some digital stepping. So unless a director specifically asks us to do it we avoid it, as do most studios.

http://www.michaeldvd.com.au/Articles/Interviews/ShrekTech.html

So anyway, it still would be nice to know how besweet's timestretch/compacting compares to a plain-vanilla stretch in a wave editor :)

[KpeX]

Ah. My mistake. I forgot that some studios do convert NTSC-PAL for Pal releases.Originally posted by Matthew
So anyway, it still would be nice to know how besweet's timestretch/compacting compares to a plain-vanilla stretch in a wave editor :) Probably almost identical.

[Matthew]

NTSC (either 23.976 or 29.97) to PAL is uncommon, I wasn't referring to that ;) I was talking about FILM->PAL, i.e. 24 fps->25 fps - not 23.976 fps->25 fps.

Every movie DVD I have, bar 2, has audio that is ~4 percent faster than the film audio track.

Because NTSC framerate is almost identical to FILM (23.976 vs 24 fps), the pitch and speed issues with FILM->PAL and NTSCFILM->PAL are almost identical.

As an example, with LOTR: The Fellowship of the Ring PAL, clicks/pops were introduced as a result of the sloppy pitch correction. Hence some argued that the audio should have been left at the higher pitch, like with many other DVDs.

So, the incorrect pitch is probably the lesser of two evils in most instances, and this is the choice made by many professionals.

I did a besweet/sound forge comparison by looking at the waves in soundforge and they were a little different, but not hugely so :)