[mythtv-users] trandcoding messes up 6 channel audio slow audio playback

[Jean-Yves Avenard]

On 31 December 2010 18:11, Gavin Hurlbut <gjhurlbu at gmail.com> wrote:
> -6dB -> / 2 or * 0.5
> -3dB -> / sqrt(2) or * 0.7 (approximately)

Forgot to say that the mythtv internal downmixer uses Dolby Prologic
II encoding matrix to downmix ; so when downmixing to stereo, not all
surround is lost and myth upmixer will mostly be able to output the
original stream.

for 5.1 -> stereo, it's about
L = L + (C - 3dB) + LS * sqrt(2/3) + RS * -sqrt(1/3)
R = R + (C - 3dB) + LS * -sqrt(1/3) + RS * sqrt(2/3)