Audio level always low

[apinto]

Good morning,

I always had a problem with my MeGUI conversions using x264 and Nero Digital Audio: when I play the resulting file, the audio is always low compared with the conversions made by other persons. In my hi-fi I can ear the others in volume level 18, but for my conversions I need to pop it up to 22 or more.

My workflow is as follows:

1. Rip with DVD Decrypter;
2. Demux with D2V creator;
3. Encode audio using Nero AAC "NDAAC-HE-MultiChannel-128kbps" profile;
4. Encode video using AVS Script Creator and one of the x264 profiles;
5. Mux with MKVtoolnix.

I'm using the default settings for pretty much everything. Do any of you guys know if there's any setting I need to change so that my audio levels are the same as the others? (also, if you have any comment on my workflow, it's much welcome!).

Thank you very much, cheers,

AP

[Ghitulescu]

What kind of audio do you have or what is the source of it?

[apinto]

Hello Ghitulescu, thank you for your reply.

I typically encode from DVD AC3. For example, my latest convertion, "Contact", has the following MediaInfo output for the source audio file:

General
Complete name : Z:\Ripping\Contact\VTS_01_1 T80 3_2ch 384Kbps DELAY -24ms.ac3
Format : AC-3
Format/Info : Audio Coding 3
File size : 394 MiB
Duration : 2h 23mn
Overall bit rate : 384 Kbps

Audio
Format : AC-3
Format/Info : Audio Coding 3
Duration : 2h 23mn
Bit rate mode : Constant
Bit rate : 384 Kbps
Channel(s) : 6 channels
Channel positions : Front: L C R, Surround: L R, LFE
Sampling rate : 48.0 KHz
Stream size : 394 MiB (100%)

Thank you again, regards,

AP


What kind of audio do you have or what is the source of it?

[Ghitulescu]

The question actually was why do you need to reencode the audio? AC3 is already 'nough compressed, compare it with say DTS ;). If you had a LPCM of 2 GB coming from say a BD it would make some sense to convert it down to say 300MB, but what gain do you achieve from ca. 300 downto 150 MB? I know there is at least one guide (using MeGUI) explaining why this (like this one here -> http://forum.videohelp.com/topic333634.html), but in my view is an additional complication.

Secondly, I'm not sure if you use the same standards like others: how do you know that other peoples' audios are louder? The mastering standards are pretty much the same however it can be that various DVDs have various levels, moreover, there are DVDs those DTS track is louder than the DD one (I have some). So, unless you have the exact audio track of the exact DVD from a different source, and they sound different, you cannot extrapolate ...

[Inspector.Gadget]

Have you checked normalize in the audio config panel?

[tebasuna51]

If your choice is volume instead quality (AAC-HE-MultiChannel-128kbps isn't for a hi-fi equipment) you can try:
- Check Apply Dynamic range Compression
- Normalize Peaks to 100 %

The quality option, if you want transcode a 384 Kb/s ac3 to aac, is:
- Don't Force Decoding via DirectShow
- Don't Apply Dynamic range Compression
- Normalize Peaks to 100 % (not necesary most the times)
- Variable bitrate (Q=0.33)
- AAC Profile Automatic

[apinto]

The question actually was why do you need to reencode the audio? AC3 is already 'nough compressed, compare it with say DTS ;).

Because my AC3 file is 380MB and the re-encoded AAC is 128MB. I prefer to invest those 250MB in image quality. Cheers,

AP

[apinto]

Thank you all for your contributions.

This is not a perception problem, or something similar. Every single DVD or AVI/MP4/MKV file that I play, encoded by other persons, is perfectly audible at volume 18 in the hi-fi (connected to my media centre PC).

With my encodings, I need to pop up the volume to 22 or 24, which amplifies the computer bus noises... I tried enabling/disabling the "Normalize peaks to 100%" without success.

Thank you again, cheers,

AP

[smok3]

just handle ac3 decoding separatedly (dunno whats the most popular app for this kind of work this days), apply heavy DRC for starters and see if that is what you are after.

[MysticE]

Thank you all for your contributions.

This is not a perception problem, or something similar. Every single DVD or AVI/MP4/MKV file that I play, encoded by other persons, is perfectly audible at volume 18 in the hi-fi (connected to my media centre PC).

With my encodings, I need to pop up the volume to 22 or 24, which amplifies the computer bus noises... I tried enabling/disabling the "Normalize peaks to 100%" without success.

Thank you again, cheers,

AP
Are these files "re-encoded AAC @ 128MB"?

You might be able to simplify your whole process using Xvid4PSP (free and it also uses Nero AAC). It normalizes the audio automatically.

[apinto]

Are these files "re-encoded AAC @ 128MB"?

You might be able to simplify your whole process using Xvid4PSP (free and it also uses Nero AAC). It normalizes the audio automatically.

Hello,

Some of them are, some aren't. What puzzles me is the fact that the levels on the original DVD seem quite normal, even when I play the AC3 file independently on VLC, but after I convert with MeGUI the resulting AAC MP4 files are constantly low. :-(

AP

[Ghitulescu]

With my encodings, I need to pop up the volume to 22 or 24, which amplifies the computer bus noises... I tried enabling/disabling the "Normalize peaks to 100%" without success.

That's really strange, something must be wrong in your settings. Normalizing to 100% and activating DRC should increase the sound loudness.

BTW, the values of 18 or 24 say nothing to me, it's 18 out of 100 or 18 out of 25? Not that would solve your problem but it give me an idea of the real difference.

PS: I never normalize up to 100%. If I have to increase the volume I would go up to 96 - 98% (about - 2-3dBfs). Most devices do not have enough headroom and therefore heavily distort the peaks. But it's my personal opinion.

[apinto]

Ghitulescu,

I think it's 18 in 28... But that's irrelevant. What's important here I that 18 is confortable for me with pretty much every source (DVD, AVI, etc.), except with the ones I encode myself.

AP


That's really strange, something must be wrong in your settings. Normalizing to 100% and activating DRC should increase the sound loudness.

BTW, the values of 18 or 24 say nothing to me, it's 18 out of 100 or 18 out of 25? Not that would solve your problem but it give me an idea of the real difference.

PS: I never normalize up to 100%. If I have to increase the volume I would go up to 96 - 98% (about - 2-3dBfs). Most devices do not have enough headroom and therefore heavily distort the peaks. But it's my personal opinion.

[tebasuna51]

Please put your MeGUI log file, when recoding ac3 to aac, to see if there are any problem in your AviSynth script or command line options.