The mystery about the audio loudness

[snowbeach]

Take a DVD movie and listen to the sound loudness. Do not change the volume bar!
Then encode the audio of the movie with vob2audio (MP3 settings: Quality High, CBR 128kbps, JointStereo) and compare the sound loudness of the created MP3 file with the sound loudness of your original DVD movie! Use always the same DVD player (e.g. WindDVD) for comparison. You can hear that the sound loudness is the same.
Then encode the audio of the movie with BeSweet1.4 (Profile: DSPguru_MP3@128kbps -> then press AC3 to MP3, AC3 file was extracted with DVD2AVI1.76) and compare the sound loudness of the created MP3 file with the sound loudness of your original DVD movie again! The result is that the MP3 created by BeSweet is not as loud as the original DVD movie sound!!! WHY???

What can I do to get high quality MP3 files from the DVD movie sound?

[DSPguru]

here's what you can do :
1. post your logfile
2. use harder dynamic compression
3. use boost
4. use two-pass gain.

[DJ Bobo]

The sound on DVD is always very low in volume.
BeSweet does a normalization to 0db to get the volume as high as possible (and that's the right thing to do!)

BTW, why is the volume of Dolby Digital Tracks so low?!

[DSPguru]

Originally posted by DJ Bobo
BTW, why is the volume of Dolby Digital Tracks so low?! a. Because they have a bigger dynamic range than mp3.
(they keep the track soft, in order to allow a truely loud explosive sound fx when they appear)
b. dialog normalization usually attenuate the sound by few dBs.
c. 5.1->2 ch downmix (when used) usually ends up with a softer signal.

[snowbeach]

Thank you for the fast response. But I am not very familiar with BeSweet. :( I know, I have to change this! What would be the command line to get high quality MP3 out of the VOB's? Did you experience the same with the loudness?

[snowbeach]

@ DSPguru

Thank you again for your posting. I have done the tasks...
The result is that the audio loudness is satisfying, but that there is some noise in the background that disturbs me. Logfile is attached.

Have you ever encoded the audio of a DVD movie with DirectShow filters. The results are really great. For me the results are "1:1" copies. Do not have high end devices at home - that is why I never have heard a difference between the encoded file with DS filters (using vob2audio or GraphEdit) and the original DVD sound. But since I have experienced some problems with DirectShow filters I want to use another way of audio encoding for the future.

Is there a solution to get these "1:1" copies? (Hopefully you know what I mean?)



LOGFILE...

BeSweet v1.4 by DSPguru.
--------------------------
Using azid.dll v1.8 (b825) by Midas (midas@egon.gyaloglo.hu).
Using lame_enc.dll v1.28 (4/6/2002), Engine 3.92 <http://www.mp3dev.org/>.
Manual Dynamic-Compression algorithm by LigH (author of WaveBooster).

Logging start : 10/19/02 , 18:03:30.

besweet d:\1\MPEG4\BeSweetv1.4\BeSweet.exe -core( -input e:\Movies\DivX\sprrr AC3 T01 3_2ch 448Kbps DELAY 0ms.ac3 -output e:\Movies\DivX\besweet.mp3 -logfile D:\1\MPEG4\BeSweetv1.4\BeSweet.log ) -azid( -n1 -c heavy -L -3db --maximize ) -ota( -G max ) -boost( /b2=5 ) -lame( --scale 1 -p --alt-preset 128 )

[00:00:00:000] +------- BeSweet -----
[00:00:00:000] | Input : e:\Movies\DivX\sprrr AC3 T01 3_2ch 448Kbps DELAY 0ms.ac3
[00:00:00:000] | Output: e:\Movies\DivX\besweet.mp3
[00:00:00:000] | Floating-Point Process: Yes
[00:00:00:000] +-------- AZID -------
[00:00:00:000] | Input Channels Mode: 3/2, Bitrate: 448kbps
[00:00:00:000] | Output Stereo mode: Dolby surround compatible
[00:00:00:000] | Total Gain: 21.756dB, Compression: Heavy
[00:00:00:000] | LFE levels: To LR -3.0dB, To LFE 0.0dB
[00:00:00:000] | Center mix level: BSI
[00:00:00:000] | Surround mix level: BSI
[00:00:00:000] | Dialog normalization: Yes
[00:00:00:000] | Rear channels filtering: No
[00:00:00:000] | Source Sample-Rate: 48.0KHz
[00:00:00:000] +-------- BOOST ------
[00:00:00:000] | Algorithm by : Dg
[00:00:00:000] | Boost Factor : 5.0
[00:00:00:000] | Limit Factor : 0.73
[00:00:00:000] +-------- LAME -------
[00:00:00:000] | 'abr 128' preset is used
[00:00:00:000] +---------------------
[02:15:23.461] W7: Downmix overflow (1: +0dB)
[02:42:23:040] Conversion Completed !
[02:42:23:040] Actual Avg. Bitrate : 125kbps
[01:30:23:000] <-- Transcoding Duration
Logging ends : 10/19/02 , 19:33:53.

[DSPguru]

i believe you gone to far. try this :
Originally posted by snowbeach d:\1\MPEG4\BeSweetv1.4\BeSweet.exe -core( -input e:\Movies\DivX\sprrr AC3 T01 3_2ch 448Kbps DELAY 0ms.ac3 -output e:\Movies\DivX\besweet.mp3 -logfile D:\1\MPEG4\BeSweetv1.4\BeSweet.log ) -azid( -c heavy -L -3db -g 0.99 ) -lame( -p --alt-preset 128 )

[snowbeach]

Thank you very much! The audio sound is now great, fantastic, ... :D
I can recommend it for everybody...