Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.


Go Back   Doom9's Forum > General > Audio encoding

Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
Old 18th July 2013, 12:42   #1  |  Link
Registered User
Join Date: Nov 2012
Posts: 30
Dialogue nightmode downmix preset for 5.1 DTS to 2.0 AAC stereo using ffmpeg and qaac

After converting many DTS movie tracks from 5.1 to 2.0 using eac3to, I have found the default eac3to channel mappings to result in very quiet dialogues and overly loud music and action scenes. Although the eac3to channel downmix coefficients have a scientific basis, they often do not sound good in practice bceause of low dialogue volume. This preset is for those looking for clear dialogues with left and right channel music still being audible but more in the background.

Requires: ffmpeg.exe and qaac.exe
ffmpeg.exe -report -loglevel verbose -i "videofile.mkv" -map 0:a:0 -f wav -acodec pcm_f32le -ac 2 -af pan=stereo:FL=FC+0.30*FL+0.30*BL:FR=FC+0.30*FR+0.30*BR - | qaac.exe --tvbr 127 --quality 2 --rate keep --ignorelength --no-delay - -o "audio-2ch-downmix.m4a"
The default eac3to channel matrix is:
FL' = 0.71*FC + FL + BL
FR' = 0.71*FC + FR + BR

This "nightmode" preset uses the following channel matrix:
FL' = FC + 0.30*FL + 0.30*BL
FR' = FC + 0.30*FR + 0.30*BR

As you can see - front center (dialogues) come in properly now and stay at the original level - while the music and explosions remain a background effect and don't overpower you. This preset solves the problem of you having to constantly fiddle with the volume knob when watching DTS 5.1 converted to 2.0 movies in order to hear dialogues. (Especially for watching movies in the night where you don't want to wake others but still want to be able to hear dialogues).

Try it out and you will notice a much better movie watching experience for 5.1 to 2.0 converted movies.

Last edited by robertcollier4; 24th March 2014 at 00:27.
robertcollier4 is offline   Reply With Quote

2.0, 5.1, downmix, dts, stereo

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT +1. The time now is 18:15.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.