Volume in AC3

[tominator]

Hi.
I encode ac3-files and mpegs to WMV-streams.

The Audio stream is 128kbit/s 48khz.

My problem is my output often has low volume and I was wondering why this is.

Should I perhaps boost my volume and if so, how do I know how much when all DVDs seem to have different volumes to begin with?

[chickenmonger]

What tools are you using to encode the WMVs? Are you using AviSynth?

[Awatef]

You're definitely missing some steps during the sound processing.
You *have* to boost the sound! It's not a choice you make, it's mandatory!
Tools like Headac3he can do this for you automatically (you don't have to find out the gain value by yourself).

[tebasuna51]

You *have* to boost the sound! It's not a choice you make, it's mandatory!
Is your opinion.
My opinion is never use boost because are generated undesired harmonics.
Instead boost use Dynamic Range Compression and after normalize.

I think is a user choice.

[raquete]

when i encode to AC3 and back to wave again the volume of the tracks are the same then,i can't find reasons to amplify,normalize or something.
the problem is in another part of your job and i can't help more because i don't know WMV-streams and how to get it.

[Awatef]

tebasuna, you probably misunderstood me. You called it normalize, I called it boost, because he used the word "boost", that's all.

And raquete, you're probably encoding to AC3 without applying dynamic range compression, resulting in an AC3 different from those you would usually find on DVDs, with very wide range.

[raquete]

And raquete, you're probably encoding to AC3 without applying dynamic range compression, resulting in an AC3 different from those you would usually find on DVDs, with very wide range.
and what you're using,film standard...light...?

thinking better: if you "boost" the audio and later apply the profile maybe you will get "low" volume normalized and who knows distorced! ? lol

[tominator]

What tools are you using to encode the WMVs? Are you using AviSynth?

I am using ProCoder 2.0

[tominator]

You're definitely missing some steps during the sound processing.
You *have* to boost the sound! It's not a choice you make, it's mandatory!
Tools like Headac3he can do this for you automatically (you don't have to find out the gain value by yourself).

Im using ProCoder 2.0 which has built in filters for audio.

The filter Normalize has two options:
1. Normalize to mean RMS of sources
2. Normalize peak to specified DB level

Since I don't understand the first option I can't say much about it.. But the second option has a default value of -3.00 which Ive tried and found that it works quite well.

But is there some kind of standard value for rips that I should be using perhaps?

[Awatef]

@ tominator
Normalizing to -3db is a very good option, 0db being the maximum. I usually apply gain to get a peak between -3 and 0db, these are good limits to work with.

@ raquete
I usually do it the way you do it, since I don't like wide dynamic ranges (and the neighbourhood too :D)

[Rockaria]

moved (http://forum.doom9.org/showpost.php?p=879230&postcount=168) : might be easier to decide without it.;)

[tominator]

@ tominator
Normalizing to -3db is a very good option, 0db being the maximum. I usually apply gain to get a peak between -3 and 0db, these are good limits to work with.


Will just normalizing to -3db be enough audio processing or should I do more?

[raquete]

Will just normalizing to -3db be enough audio processing or should I do more?
again...
thinking better: if you "boost" the audio and later apply the profile maybe you will get "low" volume normalized and who knows distorced! ? lol
not kidding,if you're not using any profile just amplify(it's not normalize) to -1dB(peak)...or better,can you post one screenshot of the waveform from your audio for fast avaliation?
regards!

[TheManuel]

What is a good -dygrng setting in Aften for home videos?
... or is "Film Standard" a good setting for DVD output regardless of the source material?

Thanks.

[tominator]

again...

not kidding,if you're not using any profile just amplify(it's not normalize) to -1dB(peak)...or better,can you post one screenshot of the waveform from your audio for fast avaliation?
regards!

Im sorry I can't post a screenshot right now.

But how do I just amplify to -1db? I don't have that option. I can only amplify the volume by a multiple of 0.1 to 2.0.

I can normalize but that filter doesnt seem to be working.

Is there a program that will let me amplify just the ac3? So that I can process it through there before I open it with ProCoder 2.

[raquete]

-1dB = ~89.13%..adjust to 90% by peak(no RMS) and don't normalize because you'll change the whole dynamic of the sound...lots don't agree with me but normailzation is "a crime".

for movies use "film standard" or "speach" for conversations (both have the same cut-range)and i don't know if have any program to amplify AC3,sorry!

about the screenshot (if you're interested) : open the audio editor with your audio,hit print-screen,open paintbrush and save somewhere.host the picture in imageshack and post the url here.

regards

[danpos]

@raquete

If I did understand correctly, you're recommending to do a amplify to -1dB on wav file and after that, to encode to ac3 using aften with options -dnorm XX -dynrng 1 (where XX is got from wavrms tool from aften package)? Plese, confirm if my findings are correct or I'm missing something.

Regards,

[tominator]

-1dB = ~89.13%..adjust to 90% by peak(no RMS) and don't normalize because you'll change the whole dynamic of the sound...lots don't agree with me but normailzation is "a crime".

for movies use "film standard" or "speach" for conversations (both have the same cut-range)and i don't know if have any program to amplify AC3,sorry!

about the screenshot (if you're interested) : open the audio editor with your audio,hit print-screen,open paintbrush and save somewhere.host the picture in imageshack and post the url here.

regards

Here's a screenshot complete with all my audiofilter options.

http://img351.imageshack.us/img351/2025/untitledcopywn4.jpg (http://imageshack.us)