On Mon, 15 Jan 2018 14:14:13 +0100, Ricard Wanderlof wrote: > > > On Fri, 12 Jan 2018, Takashi Iwai wrote: > > > > The ALSA softvol plugin has a maximum gain of 50 dB (MAX_DB_UPPER_LIMIT is > > > fixed to 50 in pcm/pcm_softvol.c). Is there some technical reason for this > > > limit? These days when >16 bit audio is becoming common, it's not > > > unreasonable to have large gain figures, and that is in fact a usecase I > > > have right now. > > > > > > I'm looking through the CONVERT_AREA and MULTI_DIV_foo macros to see if > > > there's something there that degenerates when the gain factor becomes too > > > large, but I'd thought I'd ask too rather than just do reverse > > > engineering. > > > > There is no more reason than "some reasonable limit". > > Ok, my suggestion would be set MAX_DB_UPPER_LIMIT to 90 dB. 90 dB comes > out as 31622, which still is manageable when shifted up by VOL_SCALE_SHIFT > (= 16), fitting in a 32-bit int. Thus it works in MULTI_DIV_short() too, > where it is multiplied with the 16-bit sample value yielding an int. > > I'll try it out and prepare a patch. Well, but +90dB gain doesn't look like a normal usage pattern. Why do you have to use softvol plugin for achieving that specific purpose? Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
