How to boost audio volume

[FredThompson]

I've got a title for which the audio is very quiet. (2-disc Hermitage Museum set, English track is whisper quiet, others are "normal.")

How does DVD-RB Pro handle the audio? I'm looking for a way to boost the volume, preferably without having to run the video encoding step again.

[manono]

Hi Fred-

DVD-RB just uses the audio as-is. No encoding or anything else is done to the audio.

If you want to boost the volume (which should have already been normalized), after DVD-RB is done, demux the video using PGCDemux, convert the audio to WAV, fix it however you want in a WAV Editor, and then reencode back to AC3 with the same bitrate using some AC3 encoder. Then remux everything using Muxman, replacing the original audio with the fixed audio. Take that new DVD Muxman made and, using the "Replace" button of VobBlanker, stick it back into the DVD-RB produced DVD. That's one way, anyway.

[ronin510]

by any chance are you using VLC or mplayer to play the DVDs on your computer? i've been having problems with the AC3 ch 6 sounds sounding muffled/quiet, while the AC3 ch 2 sounds are fine. these are on both original or backed-up movies.

[FredThompson]

Nope, PowerDVD. This is a problem with the original source. The English track is very faint, the others sound just fine.

manono's suggestion will work. I'm still hunting for something similar to MP3Gain for VOBs...

[techmule]

Nope, PowerDVD. This is a problem with the original source. The English track is very faint, the others sound just fine.

manono's suggestion will work. I'm still hunting for something similar to MP3Gain for VOBs...

You can add gain to the wav using HeadAC3he

[Rockas]

mmmmm... I guess you can use the demuxed AC3 and improve the gain using AviSynth... then let QuEnc do the job :)

if you need any help with the script warn me :)

[Boulder]

Fred, I don't think there's any way to boost the volume without re-encoding the audio track. Would it make sense to play with the dynamic range compression (though I'm not sure if there is a way to change the value without re-encoding either).

[jdobbs]

This is one of those things that really bugs me about many DVD audio tracks. For some reason they really lower the overall volume on DD5.1 and DTS touting that it is using a "wider dynamic range" -- I personally prefer to call it "low-ass volume". Maybe I should start looking at reencoding audio with a "normalize audio" setting.

[Boulder]

There's a new ffmpeg version which you could use, the low volume problem with 6-channel files has been fixed. That is, should you choose to use a free program for re-encoding.

[jdobbs]

Hmm... I would guess that QuEnc uses the ffmpeg version... that might make it easier since QuEnc is distributed with DVD-RB.

DragonGodz?

[steptoe]

If you are thinking of adding some sort of "normalize" audio switch then I'd be using it as a default for my stuff as I'm fed up with audio tracks being way too quiet, on some and blasting out on others


I used to do that by hand long before I found DVD-RB, in extracting the audio running it through something to boost the audio to maximum without clipping then adding it back to the authored DVD

It was a pain to do, and added loads of time to each project so gave up doing it



Can't you just use the Avisynth audio filter to boost the audio or am I being to simplistic here. Would the audio have to be extracted first

[Boulder]

Hmm... I would guess that QuEnc uses the ffmpeg version... that might make it easier since QuEnc is distributed with DVD-RB.

DragonGodz?
http://forum.doom9.org/showthread.php?p=811880

At least it has been included in the QuEnc code in some unreleased version so I guess it's in the v0.70-branch as well.

[dragongodz]

so I guess it's in the v0.70-branch as well.
from here
http://forum.doom9.org/showthread.php?t=110888
.improved ac3 encoding low volume problem
and also an extra
.changed ac3 downmix levels to -3dB and dialnorm to -27dB (Dolbys reccomended settings)

so yes it would be interesting to know how well this goes and if there are any problems to fix with it.

[FredThompson]

I'd prefer to demux, boost, remux in this case because the video encoding has already been done. CLI tools should help reduce...uh...operator error. It's also interesting to see other people run into this problem, too.

There are 2 normalizing routines with which I am familiar:

https://neon1.net/prog/normalizer.html
http://normalize.nongnu.org/

The results are not identical. They use different methods to calculate peak volume. AFAIK, these are only normalizing volume, not compressing, which should be avoided.

Am I correct that the whole process could be a batch file of muxman, HeadAC3he and one of these normalizing routines?

[steptoe]

Method I used to use was to use AC3Tool to extract the audio, and also use it to convert the AC3 to WAV, this marvelous freeware tool can also downmix from 6-ch to 2-ch and also convert AC3 to MP3

Its a bit iffy to use until you use a couple of times, and it hasn't seen an update in years, but it actually works

Then I would run the WAV file through WavGain which is basiccaly the WAV version of MP3Gain to get the loudest volume without clipping

Then add the audio back to the DVD when authoring



If DVD-RB can do something similiar by extracting the audio, then running it through similiar software to boost the volume, and then remux the audio tracks back into the DVD it would improve the already very good piece of software that DVD-RB is

[FredThompson]

Hmmm...seems there are plenty of tools to let jdobbs add this as an option.

I wonder if there is an AC3Gain, of sorts, a way to boost the volume by modifying the file, not re-encoding. The first normalizing routine I mentioned allows for impulse noise and clips it so the general volume is higher.

[jdobbs]

Right now my plan would be to decode it, normalize it, and reencode it. But it would be way cool if there was a "within-the-compressed-domain" method of increasing gain in an AC3 file.

[FredThompson]

Yeah, I was thinking something similar; one pass to detect peaks and throw out impulses so they don't skew the average and a second pass as a simple addition with some kind of limiting at the impulses so they aren't clipped.

I've asked in the audio forum here on doom9 and am doing some searching other places. Hope we come up with something to avoid re-encoding...

If not, ahead released their Nero free-use encoder a while ago, the migraine encoder has been out for a while and there's also Enhanced AAC http://www.hydrogenaudio.org/forums/index.php?showtopic=31120

edit: BeSweet has 2-pass normalization and full support for AC3. How could we have forgotten this reliable old friend?!?! I feel dirty... http://home.mindspring.com/~fredthompson/Smiley-Sneeze.gif

[dragongodz]

Hope we come up with something to avoid re-encoding...
change dial-norm metadata level instream ?
http://www.hometheaterhifi.com/volume_7_2/feature-article-dialog-normalization-6-2000.html

if i understand correctly this is only possible, to boost audio atleast, if the the lowest value of -31 is not already used. the default i have seen Dolby reccomends for action movies is -27, hence the change i made mentioned earlier.

[Darksoul71]

Let´s not forget about BeSplit !

The latest beta had also "lossless" compression for AC3 and MP3.

Have a look here in the beta section:
http://dspguru.doom9.org/

new switch : -ota( -G max ) , for normalizing mp3 & mp2 files
I´ve never tried this AC3 streams but normalizing MP3s works fine for me and I never had any issues with it.

Cheers,
D$

[dragongodz]

The latest beta had also "lossless" compression for AC3 and MP3.
hmm i can not see that mentioned anywhere. infact i would be surprised if i did considering AC3 and MP3 are lossy compression. the only thing close i see is
- now offers a loseless demuxing of stereo mp2 into two mono mp2 files.
so can you please point out where this is mentioned ?

I´ve never tried this AC3 streams but normalizing MP3s works fine for me and I never had any issues with it.
and of course Avisynth has normalisation aswell. so it would be just as possible to not have to add extra programs to do all this. simply decode and normalise with Avisynth and encode with QuEnc.

[Darksoul71]

Hi Dg,

My bad...

sry, I´ve mistaken MP3 and MP2 with AC3 and MP2 :)

Was too early this morning and I didn´t have my first cup of coffee. Nevertheless BeSweet could be the right application to do the job.
Why use AVISynth and QuEnc ? BeSweet doesn´t add too much kByte for the installation package of DVD-RB and there could be
an option within DVD-RB for each audio stream to amplify, normalize, downmix, etc.

Cheers,
D$

[dragongodz]

Why use AVISynth and QuEnc ? BeSweet doesn´t add too much kByte for the installation package of DVD-RB
and using Avisynth and QuEnc would increase the size not at all. the only tiny increase would be if i was to suggest(which i would) to include the Nicaudio Avisynth plugin for decoding the AC3.
really its just options.

an option within DVD-RB for each audio stream to amplify, normalize, downmix, etc.
all of which Avisynth,which is already used by DVD-RB, can do aswell.

[jdobbs]

Ahh... I wasn't aware of the nicaudio plugin... I'll check it out.

[I just downloaded it, I'll do some testing]

[FredThompson]

If re-encoding is necessary, it really should be done by expanding the sample resolution, adjusting then downmixing. FWIW, I'm still hoping there's a way to kick up the volume without re-encoding, sort of "moving zero", as it were...

[dragongodz]

I'm still hoping there's a way to kick up the volume without re-encoding, sort of "moving zero", as it were...
go back to the post where i mention changing dial-norm metadata. i dont know offhand any program that can currently do it but it should be possible.

[jdobbs]

@dragongodz

Any reason why the audio bitrate can only be set to a maximum of 384Kbs in QuEnc? Most of the DD5.1 streams are 448Kbs...

I did a few tests, and the "Normalize" function in AVISYNTH seems to do a pretty good job of raising the volume level on those low volume/high dynamic range sources.

[dragongodz]

Any reason why the audio bitrate can only be set to a maximum of 384Kbs in QuEnc? Most of the DD5.1 streams are 448Kbs
ummm because i havent added it yet. ;)

audio encoding has got the least amount of feedback so hasnt really been high priority.

[m1ckran]

Don't think that lack of feedback means lack of interest.

I'm sure there are many people watching this thread who would welcome some sort of normalisation in DVDRB.

It's just that non-technical people like me find it best to stay quiet if we cannot contribute to the technical debate.

I also hate the difference in sound levels and I'd welcome the ability to set the level at some constant value for all dvd's, if its possible without complicated mucking about.

[jdobbs]

I'm definitely looking at this seriously. DragonGodz and I have had a few PMs going back and forth on it as well. I personally get really annoyed when I have to turn my amplifier up to some ridiculous volume because of a "wide dynamic range" (which seems more aptly named "narrow volume"). My preference would be the "dial norm" DragonGodz mentioned. Reencoding, however, is still on my list as a possibility as it could also support 5.1 to 2.0 conversion, DTS to 5.1 conversion, etc...

[m1ckran]

I'm not sure whether DTS to Dolby would be worth your time because all DTS dvd's I own include DTS in addition to Dolby.

Whatever method you adopt (perhaps several) I'm sure it will be welcomed by many.

[l8nights]

Don't think that lack of feedback means lack of interest.

I'm sure there are many people watching this thread who would welcome some sort of normalisation in DVDRB.

It's just that non-technical people like me find it best to stay quiet if we cannot contribute to the technical debate.

I also hate the difference in sound levels and I'd welcome the ability to set the level at some constant value for all dvd's, if its possible without complicated mucking about.

exactly:cool:
I'd love to see this addition.
I've actually posted similar ?'s in several forum's looking for a simple method, just to hear many people say "ya, that's annoying" or other "methods" that made me stop asking the ? and just rely on the good ole (worn-out) volume button.

add me to the list of people anxiously waiting/watching.

[m1ckran]

SAPSTAR is also working on audio processing for AutoQMatEnc. It might be a good idea to consult and compare notes now that AQE has the jdobbs seal of approval.

Sorry if this is old news.

[FredThompson]

If re-encoding is used, please use a method with wide samples. It's far more accurate to expand the resolution, do floating point operations, then downsample than to do 16-bit operations.

Ditto to the comment about DTS and Dolby on the same disc. The only exception I can think of was one of the Gladiator editions. Didn't they have one that was DTS on one disc and Dolby on the other?

[dragongodz]

I'm not sure whether DTS to Dolby would be worth your time because all DTS dvd's I own include DTS in addition to Dolby.
i have several music related dvds that this would be good for. for example i just grabbed my wifes "Queens greatest video hits 2" and it has 3 audio tracks. track 1 is PCM stereo, track 2 is DTS 5.1 and track 3 is AC3 stereo. heres the thing though, only tracks 1 and 2 are the music. the AC3 track is a commentary track, so i dont think i would want to just have that track alone. :)

SAPSTAR is also working on audio processing for AutoQMatEnc.
if he is using AC3 encoding from libavcodec(is there another open source AC3 encoder ? even the dll used by Besweet is based on libavcodec) then what advantage would it have over QuEnc ?

[TBL]

Reencoding, however, is still on my list as a possibility as it could also support 5.1 to 2.0 conversion, DTS to 5.1 conversion, etc...

This would be great! :D
I have some DVDs with only LPCM sound where DD 5.1/2.0 would be more than adequate because the original isn't very good either. It could also be used in downsampling audio in extras and commentary in a lot of DVDs.

And I'm all for having an option to normalize it too :cool:

[Darksoul71]

SAPSTAR is also working on audio processing for AutoQMatEnc.
AFAIK SAPSTAR has currently stopped developing any audio encoding with AQE because of
some problems.

if he is using AC3 encoding from libavcodec(is there another open source AC3 encoder ? even the dll used by Besweet is based on libavcodec) then what advantage would it have over QuEnc ?
I think SAPSTAR wanted to use libavcodec for this but I think we will see audio encoding in AQE very soon
and I also see no real benefit using AQE for audio encoding if you can either use QuEnc or Besweet.

[m1ckran]

I never suggested that one approach might be better than another, only that many hands might make light work.

[Darksoul71]

@m1ckran:
I didn´t want to sound offensive. Agreed, many hands often help to make things easy. I just wanted to point out that (from my point of view) there is no big difference wether you (in terms of "you, the developer") use either BeSweet, QuEnc or AQE (with a currently non-existing audio encoding module). Nothing more...

Later,
D$

[m1ckran]

No problem. Perhaps I implied favouritism when none was intended. I certainly don't have the technical expertise to express a preferrence. :)

[jdobbs]

change dial-norm metadata level instream ?
http://www.hometheaterhifi.com/volume_7_2/feature-article-dialog-normalization-6-2000.html

if i understand correctly this is only possible, to boost audio atleast, if the the lowest value of -31 is not already used. the default i have seen Dolby reccomends for action movies is -27, hence the change i made mentioned earlier. Well I've experimented with changing dialnorm (I finally got it to work) -- and the only way to increase the volume is to set the value higher (from the default of -27db to -31db) -- which raises the volume, but not very much. I may add it as an option, though, anything is good.

Too bad this was a good possibility.

One thing I found odd... if I changed the dialnorm value of any of the first 4 frames it would cause the player to fail with "unsupported format" -- does anyone have a clue why that is so?

[Susana]

Changing dialnorm affects Dymanic Range Compression algorithm. Not good idea, I think.

The following point, however, cannot be stressed enough: In order for the Dynamic Range Compression to work as designed, the Dialogue Normalization parameter MUST be properly set first!

http://forum.doom9.org/showthread.php?p=332259#post332259

Though 4 dB is not much.

[jdobbs]

I did some testing and I think upping the dialnorm to -31db seems to cause some "pumping" on the higher volume areas... I think I'm going to abandon that idea. Right now it appears the only choice is to normalize during reencoding -- which is really a PITA. :(