AC3 audio editor.

[darkflux]

you can definitely do it!
https://forum.videohelp.com/viewtopic.php?p=1660216
VOBDNorm 1.0
it just changes the dialog normalization value (a number which has a value of between 0 and -31). i first learnt of dialog normalization from Sound Forge, which allows you to specify a value when you save the AC3.
i WASN'T however, aware you could change an mp3's norm levels without a good re-encode, so you've helped ME out as well! thank you definitely gonna try that prog.

just a little side note: this "dialog normalization" setting is a setting created to differentiate volume levels between a program and commercials (potentially, anyway). no data is actually gained or lost, and the fidelity itself isn't altered, it's just a setting to tell the "player" how loud to play the existing sound data. a nice idea, in theory. ironically, lower values are better (for boosting volume). -27 is average. for more on this:
http://en.wikipedia.org/wiki/Dialnorm

[Killer3737]

Ahh that sounds pretty useful for now. Thanks. That's all normalizing is doing anyway basically, boosting the volume. You can undo normalization by turning down the volume really. It's just a pain when you have a digital stream and the AC3 volume is really low. I used to just convert to WAV and normalize that.

[darkflux]

yes, but if you have to convert to wav and then RECOMPRESS to ac3, you lose a little of that fidelity that was there before...this circumvents that loss!

[dishwara]

I don't know u got the result or not.
Anyway to edit ac3 files u can use nero wave editor.
go to http://www.bitburners.com/software/dolby-ac3-v10032/3810/
download the file & paste it in C:\Program Files\Common Files\Nero\AudioPlugins or C:\Program Files\Common Files\ahead\AudioPlugins. u will see other nxMy***.dll files.
In nero wave editor, go to Options->Audio format settings->dolby digital (Ac3). click configure & in output channel sequence click 5.1 instead of downmix.
Now u can open ac3 files & see five or six separate channels.
Also in bottom left corner u see a speaker graphics displaying separate channels. Also u can volume change INDIVIDUAL channels.
in volume change ->active channels select the only channel u want to edit.
Try different options.

[darkflux]

nice hack dishwara
wasn't aware Nero could open AC3's, as i usually use Sound Forge (which is a bit pricier than Nero).
i just tried it, and it worked great.
thanx,
df

[AlanHK]

nice hack dishwara
wasn't aware Nero could open AC3's, as i usually use Sound Forge (which is a bit pricier than Nero).
i just tried it, and it worked great.

Does Nero really open AC3 as AC3?
I bet it just converts to wave and recompresses on export.
If it takes a longish time to open a file, and creates a large temproary file, that confirms it.

Anyway, the latest version of Audacity (1.3.6) can both import and export AC3, if you configure ffmpeg as a filter.
And it's free.

[darkflux]

Alan, i'm not aware of ANY audio editing software that DOESN'T open files as temporary WAV files. they're more convenient to edit, and because you're editing the physical content of the file, you'll be re-encoding anyways, so you might as well open it in a convenient format. most audio editing tasks require re-encoding, and most tasks that don't re-encode, usually require separate programs and are not as comprehensive changes as what you can do with a WAV file.
in fact, Audacity opens ac3's as wav files, too. it still does an awesome job editing though
so yeah, all-in-all Audacity's editor is about the same as Nero's editor...except that Audacity is free.
cheers

[dishwara]

@darkflux: glad it helped u.
@AlanHK: I tried audiocity 1.3.7 beta with ffmpeg as it suggested from preference->import/export. But it can only load 3 or 2 channels not all 5 or 6 channels as nero.
Whether u buy it or not u have nero since most dvd writers include this as default software.

I tried with Sony sound forge 9 & it says file could not be opened , unsupported format.
While VLC & MPC plays it fine.
Anyhelp to solve?
Thanks.

[AlanHK]

Alan, i'm not aware of ANY audio editing software that DOESN'T open files as temporary WAV files.

For MP3 there's MP3DirectCut.
For AC3, DelayCut can cut segments from AC3, and Audioscale can stretch or compress the length, by dropping or duplicating frames.

But anything that does any filtering/effects will need to decompress them.
And I suppose there must be a transient uncompressed stream to play audio, or display the waveform.

in fact, Audacity opens ac3's as wav files, too.

That's what I meant by "import" and "export", though it actually uses its own ".au" format files when working, which can be saved as a "project".

[gadgetguy]

I tried audiocity 1.3.7 beta with ffmpeg as it suggested from preference->import/export. But it can only load 3 or 2 channels not all 5 or 6 channels as nero.

Huh? Audacity opens 6 channel AC3 for me.

[dishwara]

All of a sudden now i can only see front left, front right & center channels.
nero, audiocity , sound forge , VLC, MPC, winamp everything shows only 3 channels. The ac3 filter also shows only 3 channels.
The rear left, rear right & LFE are gone.
can anyone know this.
I checked the speaker configuration & its in 5.1
Not able to hear & also not even able to see in editors.
someone help me to get 6 channels back.
Thanks.

[Alex_ander]

I tried with Sony sound forge 9 & it says file could not be opened , unsupported format.

I recently managed to open a VOB with 5-channel ac3 in SoundForge (you can detach video after import). Unlike the case with 2-channel ac3's, simply renaming ac3 to VOB does not work for 5-channel audio files. So muxing ac3 to some VOBs is a possible workaround.

[darkflux]

dishwara, not all ac3 files are 5.1 surround, some, such as those captured from TV shows and some DVD commentaries, etc., are only 2.1 (either L&R plus center or L&R plus Bass). if you're certain this is NOT the case, i'd start checking your settings, or temporarily disabling AC3 Filter. whatever codec it is using is not set up right...
as for Sound Forge 9, you need to mux it with another video file, like an MPG file works great. i use Womble MPEG Editor for this, but i'm sure there's freeware available for this. you can save it as a multi-track AC3 in SF9 with no problems afterward.
also, playing a file is different from being able to open it. it requires the program to be able to use the filter, and not all codecs work that way...

Alan, for the record i didn't consider "cutting" files as editing since nothing changes about the file, just when it starts/stops. i hadn't heard of Audioscale, but it sounds useful for specific purposes. you wouldn't happen to have a link where i could download it from, perchance

on a slightly unrelated note, i wonder why it needs so many .au files to work with? also, .au files were originally Linux .snd files, but Audacity's .au's seem to be a different format alltogether. interesting.

[dishwara]

the files are 5.1 files. when i opened with nero it showed 6 tracks.
Now whatever 5.1 ac3 file i open only 3 channels there.
also VLC & MPC plays only 3 channels & i get no sound from rear left & right & Lfe.
Also i checked the ac3 filter, it shows only 3 channels in INPUT.
it seems windows not allowing more than 3 channels now.

[darkflux]

dishwara, in MPC go to View > Options > Internal Filters > Transform Filters, and double-click AC3 and check the options for surround settings.

in VLC click Audio > Audio Device, and click on 5.1 (or A/52 over S/PDIF), and check out Tools > Messages. it should say how many channels it can see, even if you're only using stereo speakers. also, Tools > Preferences > Audio, and set "Force Dolby Detection" to "On" (or "Auto").

barring all else, you might check your sound card's settings, and if nothing else seems to work, be sure your surround speakers didn't come loose (believe it or not i had that happen one time RIGHT AFTER HOOKING THEM UP! i felt like an idiot, but i learnt to take nothing for granted.

let me know how it goes.

[AlanHK]

Alan, for the record i didn't consider "cutting" files as editing since nothing changes about the file, just when it starts/stops. i hadn't heard of Audioscale, but it sounds useful for specific purposes. you wouldn't happen to have a link where i could download it from, perchance

Cutting certainly is "editing". And it's about the only editing you can do in the compressed format.
As for Audioscale, the original page is dead, but you can find it on the Wayback Machine:
http://web.archive.org/web/*/http%3A//thunder.eeap.cwru.edu/~zhuo/audioscale.html
Someone on Doom9 made a GUI: http://forum.doom9.org/showthread.php?p=797909#post797909
I attach a zip including both.

audioscale.zip

on a slightly unrelated note, i wonder why it needs so many .au files to work with? also, .au files were originally Linux .snd files, but Audacity's .au's seem to be a different format alltogether. interesting.

They're an internal format, not intended for use by other apps.
Saves seeking through and writing the very large files it would need if they were monolithic.
Also, Audacity has infinite undo, which is implements by keeping copies of the relevant changed .au files.

[dishwara]

dark flux i need a favor.
I did all as u mentioned. Now some files are 5.1 whiles others r 3 channels.
please download song from this page & tell whether its a 5.1 or 3. here it shows 3 channels only.
http://rapidshare.com/files/190674895/Padikathavan.5.1.DB.Hey.Rosu.Rosu.LS.ac3
Thanks.

[darkflux]

no problem dishwara, the files are in 5.1 format, but only 3 of the channels contain sound. i tested this in several programs (and my speakers), and they all came up the same.

AlanHK, thanks for the new program also, i could understand keeping minimal files for space reasons, but when i open a 20MB file, it creates 170MB worth of TEMP files, whereas Nero's Wave Editor makes just 2 files with a total of 3MB in TEMP files. not sure how not making a big file matters if it just makes a bunch of files totaling a larger amount, unless i'm missing something?

[AlanHK]

AlanHK, thanks for the new program also, i could understand keeping minimal files for space reasons, but when i open a 20MB file, it creates 170MB worth of TEMP files, whereas Nero's Wave Editor makes just 2 files with a total of 3MB in TEMP files. not sure how not making a big file matters if it just makes a bunch of files totaling a larger amount, unless i'm missing something?

If a section is edited, they only need to keep a copy of the relevant segment file. Maybe Nero does it virtually, all within the same file, if it keeps the same level of undos at all.

Anyway, you can ask the coders at the Audacity forum if you want a definitive answer

[darkflux]

yeah, i was thinking that, too; maybe it needs the space for the infinite undos. not sure how Nero's works, but i know Sound Forge will use however much hard drive space you have.
'scool, thanks for the info man : )

[dishwara]

Thanks darkflux.
now i am sure my pc has no problem.
Nero has a not good feature.
When we open an ac3 file it creates a peak file & stores it. u can see it in editor options-> directories.
If we again open the file instead of creating again it uses the old peak file.
If source is edited or changed, it doesn't shown when opening.
enable always create peak files.

[darkflux]

actually, the peak file is a GOOD thing (when properly implemented). it allows you to have a visual representation of the audio file (as shown by the "zig-zag" lines you see when you open the file), in addition to being able to process audio more quickly, because it contains all the details of the audio file. the BAD thing is when it doesn't delete that file afterwards. i'm guessing that Nero figured people would be saving the file with a different name (which is what i do), such as "filename (edited).ac3", or "filename2.ac3", so i can tell which was the original file during a project. Sound Forge does this too, though in it you can set it to delete them on close in the options. to disable this in Nero, you can just delete the text in the "Peak File Directory" box in the options, and confirm when it warns that the folder doesn't exist. this should keep it from creating a peak file, but you may be limited on the functions when editing. just an FYI.
also, i should note that in Sound Forge there's also an option to rebuild track data (peak file), so in case something happens, you can have it start from scratch. Sound Forge places the peak file in the same directory as the source file, too, sop it's easy to tell if it's not doing it's job for some reason. another reason i use it primarily.

[dishwara]

Thats right. I don't mean the peak file feature is bad. But instead of saving it, it should be deleted in default configuration.
In opening one file i clicked cancel & it showed a half peak file.
Next time i opened the file again it show only half file.
I manually deleted that file to create & enable the option, so that next time it creates the file.

[darkflux]

sounds good. you just have to remember to delete the peak file before re-editing...but you SHOULDN'T HAVE TO! what i mean is that that shouldn't be the way a program is. it should be not only intuitive, but customizable as well, because, let's face it, not everybody uses a program the same way (or for the same purpose). then again, maybe they do that to make the next release seem better...still, it shouldn't be left that way. they could release an update to fix the issue.

are you listening Ahead Software?

</RANT>

sorry bout that, just had to get it off my mind

[dishwara]

Lets hope they hear.

[Bully9]

I found this thread looking for a way to lower the bitrate on a 6 channel ac3 file. I've got as far as loading the ffmpeg filters for Audacity and opening the file into 6 'windows'.

Is it possible now to reduce the bitrate of the original? I presume i will have to export these 6 tracks as ac3 and choose the new bitrate, but i can't quite work out how to do it.

Can anyone help. please?

[dishwara]

Very simple. Just select all tracks. ctrl+A, Then alt+T(Tracks)->Resample.
Select new sample rate like 8000 & ok.
It will convert all tracks to 8000.
u can also change format.
select the track, click the down arrow (with song name) next to X-> set sample format-> choose u want.

[Bully9]

Thanks for the reply dishwara, but i don't understand what you're saying.

This may be because i don't fully understand what i'm doing.

But I don't want to change the sample rate (48000), i want to change the bit rate of the original (from 448 to 384) and save/export as one ac3 file.

In othe words, I have an ac3 file which is 448 kbps that i want to convert to 384 kbps.

[Safesurfer]

Export File>Choose Save As type AC3 (FFMPEG)>Click Options, that's where you can set the Bitrate.

[Bully9]

That's the kiddie I was messing around with export multiple and various other options.

Many thanks safesurfer.