On May 13 23:05:51, jn.ml.sxu.88@xxxxxxxxxxxxxxxxxxxx wrote: > On 2024-05-13 20:30, Jan Stary wrote: > > > /Users/minion/sox/rec DBUG effects: sox_add_effect: extending > > > effects table, new size = 8 > > > /Users/minion/sox/rec DBUG remix: 0: > > > /Users/minion/sox/rec DBUG remix: 0 0.333333 > > > /Users/minion/sox/rec DBUG remix: 8 0.333333 > > > /Users/minion/sox/rec DBUG remix: 16 0.333333 > > > /Users/minion/sox/rec DBUG remix: 1: > > > /Users/minion/sox/rec DBUG remix: 1 0.333333 > > > /Users/minion/sox/rec DBUG remix: 9 0.333333 > > > /Users/minion/sox/rec DBUG remix: 17 0.333333 > > > /Users/minion/sox/rec DBUG remix: 2: > > > /Users/minion/sox/rec DBUG remix: 2 0.5 > > > /Users/minion/sox/rec DBUG remix: 10 0.5 > > > /Users/minion/sox/rec DBUG remix: 3: > > > /Users/minion/sox/rec DBUG remix: 3 0.5 > > > /Users/minion/sox/rec DBUG remix: 11 0.5 > > > /Users/minion/sox/rec DBUG remix: 4: > > > /Users/minion/sox/rec DBUG remix: 4 0.5 > > > /Users/minion/sox/rec DBUG remix: 12 0.5 > > > /Users/minion/sox/rec DBUG remix: 5: > > > /Users/minion/sox/rec DBUG remix: 5 0.5 > > > /Users/minion/sox/rec DBUG remix: 13 0.5 > > > /Users/minion/sox/rec DBUG remix: 6: > > > /Users/minion/sox/rec DBUG remix: 6 0.5 > > > /Users/minion/sox/rec DBUG remix: 14 0.5 > > > /Users/minion/sox/rec DBUG remix: 7: > > > /Users/minion/sox/rec DBUG remix: 7 0.5 > > > /Users/minion/sox/rec DBUG remix: 15 0.5 > > > > This must be how the 18 input channels contribute > > to the 8 output channels, in a round-robin fashion, apparently. > > Which is probably not what you want: 0 to 15 contribute as > > the two channels into 0-8 each, and then 16 and 17, respectively, > > are the third contributor to 0 and 1, respectively; > > the fractions are most probably the relative volumes. > > It's just as well there's no audio (or supposed to be, anyway) > arriving on channels 9-18 (ie those shown as 8-17 (numbered > as offsets from 0 here). No, it is still wrong: output channel 0 gets its volume attenuated to one third, the other two contributirs taking an equal 0.333 of the volume (silnece in fact). > But if sox is notionally mixing audio from 18 channels down to 8 > (which is what the manual says the "channels" effect does), it's > unnecessary work when only remix's channel select logic is needed. > The sox command needs changed so that the "channels" effect is not > being used. You are right. > IIUC it's because of the use of "-c n" in the command. (See the text > for the "channels" effect, in the manual). It seems to me that "-c n" > needs removed, because sox has to process what its being sent, > & remix alone should be used to choose which of the arriving 18 > channels are passed onwards to the output. Yes. Taking a smaller example of the same: $ sox -n in.wav synth 10 sin 100 sin 200 sin 300 sin 400 sin 500 gain -6 $ sox -V4 in.wav -c 2 bad.wav $ sox -V4 in.wav good.wav remix 1 2 $ soxi in.wav bad.wav good.wav The first command downmixes the five channels to two channels, similar to what Michael's debug output shows: sox DBUG remix: 0: sox DBUG remix: 0 0.333333 sox DBUG remix: 2 0.333333 sox DBUG remix: 4 0.333333 sox DBUG remix: 1: sox DBUG remix: 1 0.5 sox DBUG remix: 3 0.5 THe second command does the right thing: input channel 1 contributes to the first output channel, onput channel 2 contributed to the second output channel. sox DBUG remix: 0: sox DBUG remix: 0 1 sox DBUG remix: 1: sox DBUG remix: 1 1 (There is an of-by-one discrepancy in the _naming_ of the channels, because "0" in remix means "create a channel of silence". Tried the same with "remix 2 3" etc.) So what Michael wants is probably rec ... recording.aif remix 1 2 3 4 5 6 7 8 and later remix offline into the stereo pairs. Jan _______________________________________________ Sox-users mailing list Sox-users@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/sox-users
