BBC BASIC for Windows
Programming >> Sound, Music and Video >> Multiple WAV playback
http://bb4w.conforums.com/index.cgi?board=multimedia&action=display&num=1382970695
Multiple WAV playback
Post by 5against4 on Oct 28th, 2013, 2:31pm

i'm a composer & am currently creating a program that plays back various soundwaves simultaneously according to a predefined but indeterminate (i.e. partly randomised) structure. i've developed the program using elements from this article - http://bb4w.wikispaces.com/Playing+multiple+WAV+files - but i'm finding that it's a little CPU hungry, particularly when run on a PC with an older (dual core) processor, and also rather glitchy (it's fine on my quad core i7 laptop however). In this particular program, there are up to eight WAVs being played simultaneously.

So i would like to know if this might be because the file isn't reading the WAVs from memory, & if so, could someone assist with the necessary code to load/read from memory (bearing in mind i'm working with playback of simultaneous WAVs). i'd basically like to lighten the CPU load as much as possible. The relevant portion of the program is listed below.

& on a related note, is there a way to use a FLAC codec instead of the built-in WAV codec?

many thanks!
Simon

Code:
   80 layers=8
   90 DIM layer$(layers,12),reply$(layers,2),wavperc$(layers),start(layers),currentwav(layers),begun(layers)
  100 url$=""
  110 RESTORE 180
  120 FOR loop=1 TO layers
  130   READ start(loop),layer$(loop,0)
  140   FOR loop2=1 TO VAL(layer$(loop,0))
  150     READ filename$:layer$(loop,loop2)=url$+filename$+".wav"
  160   NEXT
  170 NEXT
  180 DATA 0,11,h1,h2,h3,h4,h5,h6,t20,t20,t30,t30,t60
  190 DATA 1500,12,h1,h2,h3,h4,h5,h6,t20,t20,t30,t30,t45,t60
  200 DATA 4000,11,h1,h2,h3,h4,h5,h6,t20,t30,t30,t45,t60
  210 DATA 10500,9,b1,b2,b3,b4,b5,b6,t20,t30,t30
  220 DATA 12000,9,b1,b2,b3,b4,b5,b6,t20,t20,t30
  230 DATA 15000,10,b1,b2,b3,b4,b5,b6,t20,t30,t30,t45
  240 DATA 18000,11,n1x,n2x,n3x,n4x,n5x,n6x,n7x,t45,t45,t60,t60
  250 DATA 20000,11,w1,w2,w3,w4,w5,w6,w7,w8,t45,t60,t120
  260 a=0
  270 FOR loop=1 TO layers:reply$(loop,1)="_":reply$(loop,2)="-":NEXT
  280 
  290 REPEAT
  300   FOR check=1 TO layers:REM This check is for whether a new sound should begin
  310     IF a=0 THEN TIME=0
  320     flag=FALSE:IF TIME<start(check) THEN reply$(check,1)="_":reply$(check,2)="-":GOTO 410
  330     begun(check)=1
  340     IF a=start(check) OR reply$(check,1)=reply$(check,2) THEN flag=TRUE
  350     IF flag=TRUE THEN n=VAL(layer$(check,0)):n_wav=RND(n):currentwav(check)=n_wav
  360     IF flag=TRUE THEN SYS "mciSendString", "close wav"+STR$(check), 0, 0, 0
  370     IF flag=TRUE THEN SYS "mciSendString", "open """ + layer$(check,currentwav(check)) + """ alias wav"+STR$(check), 0, 0, 0
  380     IF flag=TRUE THEN SYS "mciSendString", "play wav"+STR$(check), 0, 0, 0
  390     REMIF flag=TRUE THEN PRINTTAB(5,check);"Playing layer ";check
  400     REMpause=GET
  410   NEXT
Re: Multiple WAV playback
Post by admin on Oct 28th, 2013, 3:13pm

on Oct 28th, 2013, 2:31pm, 5against4 wrote:
i'm finding that it's a little CPU hungry, particularly when run on a PC with an older (dual core) processor

Unfortunately you've not listed the entire program, so it's hard to advise. I would expect that a program playing audio (even multiple channels of audio) would use up very little CPU time, since the computational requirements are small compared with, say, playing HD video.

If Task Manager is reporting a significant amount of CPU time being taken up by your program then you can use the Trace option (Utilities menu) to get a rough idea of where the time is being spent, and the Profiler Utility (same menu) if you want to get more quantitative results.

I would expect nearly all the time, perhaps 99%, to be spent in a WAIT statement (or equivalent, e.g. INKEY function or Sleep API).

Quote:
on a related note, is there a way to use a FLAC codec instead of the built-in WAV codec?

FMOD supports FLAC. Many BBC BASIC programs (particularly games) have used FMOD for their audio output.

Richard.
Re: Multiple WAV playback
Post by 5against4 on Oct 28th, 2013, 3:38pm

Many thanks for the quick reply Richard. Sorry for not including the whole program - see below.

Using the Trace function it's clearly the monitoring of how far through the WAVs that's taking up most of the processing. Do you think this would be reduced at all by reading the WAVs from memory instead of from disk?

Thanks for the tip off about FMOD - i'll investigate right away.

Code:
   10 REM http://bb4w.wikispaces.com/Playing+multiple+WAV+files
   20 ON ERROR ON:COLOUR9:OSCLI "FONT "+"Consolas"+","+"14":PRINTTAB(0,5):REPORT:PRINT" at line ";ERL:END
   30 MODE 30:OFF
   40 SYS "ShowWindow", @hwnd%, 3 : REM. SW_MAXIMIZE
   50 COLOUR15:OSCLI "FONT Myriad Pro,20"
   60 PRINT"Display on?";:REPEAT:disp$=GET$:UNTIL disp$="Y" OR disp$="y" OR disp$="N" OR disp$="n":CLS
   70 display=TRUE:IF disp$="N" OR disp$="n" THEN display=FALSE
   80 layers=8
   90 DIM layer$(layers,12),reply$(layers,2),wavperc$(layers),start(layers),currentwav(layers),begun(layers)
  100 url$=""
  110 RESTORE 180
  120 FOR loop=1 TO layers
  130   READ start(loop),layer$(loop,0)
  140   FOR loop2=1 TO VAL(layer$(loop,0))
  150     READ filename$:layer$(loop,loop2)=url$+filename$+".wav"
  160   NEXT
  170 NEXT
  180 DATA 0,11,h1,h2,h3,h4,h5,h6,t20,t20,t30,t30,t60
  190 DATA 1500,12,h1,h2,h3,h4,h5,h6,t20,t20,t30,t30,t45,t60
  200 DATA 4000,11,h1,h2,h3,h4,h5,h6,t20,t30,t30,t45,t60
  210 DATA 10500,9,b1,b2,b3,b4,b5,b6,t20,t30,t30
  220 DATA 12000,9,b1,b2,b3,b4,b5,b6,t20,t20,t30
  230 DATA 15000,10,b1,b2,b3,b4,b5,b6,t20,t30,t30,t45
  240 DATA 18000,11,n1x,n2x,n3x,n4x,n5x,n6x,n7x,t45,t45,t60,t60
  250 DATA 20000,11,w1,w2,w3,w4,w5,w6,w7,w8,t45,t60,t120
  260 a=0
  270 FOR loop=1 TO layers:reply$(loop,1)="_":reply$(loop,2)="-":NEXT
  280 
  290 REPEAT
  300   FOR check=1 TO layers:REM This check is for whether a new sound should begin
  310     IF a=0 THEN TIME=0
  320     flag=FALSE:IF TIME<start(check) THEN reply$(check,1)="_":reply$(check,2)="-":GOTO 410
  330     begun(check)=1
  340     IF a=start(check) OR reply$(check,1)=reply$(check,2) THEN flag=TRUE
  350     IF flag=TRUE THEN n=VAL(layer$(check,0)):n_wav=RND(n):currentwav(check)=n_wav
  360     IF flag=TRUE THEN SYS "mciSendString", "close wav"+STR$(check), 0, 0, 0
  370     IF flag=TRUE THEN SYS "mciSendString", "open """ + layer$(check,currentwav(check)) + """ alias wav"+STR$(check), 0, 0, 0
  380     IF flag=TRUE THEN SYS "mciSendString", "play wav"+STR$(check), 0, 0, 0
  390     REMIF flag=TRUE THEN PRINTTAB(5,check);"Playing layer ";check
  400     REMpause=GET
  410   NEXT
  420   
  430   a=a+1
  440   FOR calc=1 TO layers:REM This calculates how far each layer is through each sound & displays the results (omitted if display not required)
  450     reply$(calc,1) = STRING$(16, CHR$(0))
  460     reply$(calc,2) = STRING$(16, CHR$(0))
  470     SYS "mciSendString", "status wav"+STR$(calc)+" length", reply$(calc,1), LEN(reply$(calc,1)), 0
  480     SYS "mciSendString", "status wav"+STR$(calc)+" position", reply$(calc,2), LEN(reply$(calc,2)), 0
  490     IF display=FALSE THEN 570
  500     IF begun(calc)=1 THEN wavperc=INT((VAL(reply$(calc,2))/VAL(reply$(calc,1)))*100) ELSE wavperc=0
  510     wavperc$(calc)=LEFT$(STR$(wavperc),4)
  520     COLOUR15:PRINTTAB(3,1);INT((TIME/100)/60);"’";INT(TIME/100) MOD 60;"”";SPC(10);TAB(10,1);TIME
  530     PRINTTAB((calc-1)*15+3,4);calc;" (";start(calc);")"
  540     IF begun(calc)=1 THEN PRINTTAB((calc-1)*15+3,5);LEFT$(layer$(calc,currentwav(calc)),LEN(layer$(calc,currentwav(calc)))-4);SPC(10)
  550     VDU19,calc,16,INT(VAL(wavperc$(calc))*2.55),INT(((VAL(wavperc$(calc)))-100)*-2.55),0:COLOURcalc:PRINTTAB((calc-1)*15+3,6);wavperc$(calc);"%";SPC(10)
  560     REMPRINTTAB((calc-1)*15+2,4);calc;" (";start(calc);")";TAB((calc-1)*15+2,5);reply$(calc,1);" : ";reply$(calc,2);SPC(10)
  570   NEXT
  580   REMPRINT"";a;"|";SPC(5);reply$(1,1);" : ";reply$(1,2);SPC(10);reply$(2,1);" : ";reply$(2,2);SPC(10);reply$(3,1);" : ";reply$(3,2)
  590   
  600   
  610 UNTIL FALSE
Re: Multiple WAV playback
Post by admin on Oct 28th, 2013, 4:01pm

on Oct 28th, 2013, 3:38pm, 5against4 wrote:
Many thanks for the quick reply Richard. Sorry for not including the whole program - see below.

At a quick glance I can't see a WAIT (or other delay statement) anywhere in your program. If that's right it would imply that you have inadvertently coded an 'infinite loop' - i.e. a program which needlessly uses up 100% CPU time chasing around a loop. See this recent thread which discusses the issue:

http://bb4w.conforums.com/index.cgi?action=display&board=communication&num=1382121935&start=0#1382128956

If that's what is happening it could easily explain the symptoms you described.

We have moved on from the days of the BBC Micro, when it was reasonable for a program to keep the CPU fully occupied, despite not doing anything useful. Now, multi-tasking is the norm and every program needs to be written with due consideration for other programs and processes that share the CPU, memory etc.

Richard.
Re: Multiple WAV playback
Post by 5against4 on Nov 5th, 2013, 10:48am

Thanks for this Richard. i confess i hadn't realised about the WAIT command, & it certainly makes a huge difference in terms of CPU drain.

Regarding the FLAC codec you mentioned, FMOD, can that be called/used from within a BASIC program? Looking at their website hasn't quite left me much the wiser...
Re: Multiple WAV playback
Post by admin on Nov 5th, 2013, 11:28am

on Nov 5th, 2013, 10:48am, 5against4 wrote:
Regarding the FLAC codec you mentioned, FMOD, can that be called/used from within a BASIC program?

Oh yes, absolutely. I've not used it myself, but I know several people have, particularly in games.

I would have hoped that at least one of said people would have written a Wiki article describing how to do it, but having just looked there's nothing. I'm actually rather saddened by that.

Richard.