Per-channel volume correction

Hi,

Does anyone knows how hard it would be to have a per-channel volume correction ?
The reason I'm asking is that it seems that cable operators can't get the volumes of all their channels normalized. So you have to change the volume each time to get a more or less constant volume.

Another interesting feature would also be to detect commercials in order to counter their systematic increase of the volume.
An even better one would be, of course, to remove the commercials.

Regards,

Christian

[scoop]

Hi,

Originally Posted by cmorant

Does anyone knows how hard it would be to have a per-channel volume correction ?
The reason I'm asking is that it seems that cable operators can't get the volumes of all their channels normalized. So you have to change the volume each time to get a more or less constant volume.

Both the DScaler and the MPEG2 audio codec have the "Dynamic range control" feature for this. It'll increase the volume dynamically. I personally prefer not to use this option, since it has side-effects, too. BTW, many TV's use the same kind of technique to level the audio, too.

The biggest problem lies with the TV stations themselves, not the cable operators. They all use different audio proccessing settings (one more aggressive than the other). The same goes for radio stations. They use compression techniques to pump up softer sounds. And different stations use different audio compression ratios... This results in audio being at the same volume (at the signal level), but it "feels" much louder because the average sound level is way higher. That's why normalization often doesn't do what you want, because it only handles the (maximum) signal level, and does not add compression to the signal.

Kind regards,
Michel