[bb] Streaming sounds by King Dave [ 1+ years ago ]

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Title : Streaming sounds
Author : King Dave
Posted : 1+ years ago

Description : Small example to show how you can stream sounds (ie. play before the entire file is available, eg. while it is downloading from a website)

Uses a file on your hard disk and slowly transfers it to a tempory file while playing

Tested with .wav .mp3 and .ogg all worked with no problems

Only problem is, if PlaySound reaches somewhere before its been copied over, the music will stop and can't be resumed from that point

Code :

Code (blitzbasic) Select Expand

;Title: Streaming sounds
;Version: 1.00

;Author: David Blasdell (aka. King Dave)
; Email: admin@netcharger.co.uk
; Web: www.netcharger.co.uk or www.freeworldonline.co.uk

;Description:
; Example source code to demonstrate how to stream sound files using PlayMusic(filename$)
; (ie. playing the file before the entire file is downloaded)
; Transfers a file from somewhere on your hard disk to a tempory file, while it is playing
; Could be used to play music while it downloads off of a website

;Notes:
; If you enter too lower bytes per second value, the music may stop playing before the whole file is transfered


Graphics 640,480,16,2 ;Set graphics to 640x480x16 window mode
SetBuffer BackBuffer() ;Set buffer to back buffer
SetFont LoadFont("Arial",14) ;Use Arial fsize 14 as the font

filename$=Input$("Enter location of the file to be streamed: ") ;Get file to use (most things that can be played by PlayMusic() should work)
bps=Int(Input$("Enter how many bytes to copy per second (eg. 10000): "))/4 ;Will transfer this number of bytes to the stream every second

file_in=ReadFile(filename$) ;Read input file
If Not file_in Then RuntimeError "Failed to read from '"+filename$+"'!" ;If failed to read from file, say so
fsize=FileSize(filename$) ;Retrieve total fsize of file
bytes=fsize ;Used to count down bytes left to read

;Retrieves file extension
For a=Len(filename$) To 1 Step -1
If Mid$(filename$,a,1)="." Then ext$=Right$(filename$,Len(filename$)-a):Exit
Next

temp_file$=SystemProperty("tempdir")+"stream."+ext$ ;Create a tempory filename to use
file_out=WriteFile(temp_file$) ;Write to a tempory file
If Not file_out Then RuntimeError "Failed to write to '"+temp_file$+"'!" ;If failed to write to file, say so

bank=CreateBank(bps*8) ;Create a bank big enough for 2xbps worth of bytes

ReadBytes(bank,file_in,0,bps*8) ;Read bytes from input stream
bytes=bytes-(bps*8) ;Reduce byte count
WriteBytes(bank,file_out,0,bps*8) ;Write bytes to output stream (need a fair amount or bytes ready before starting PlayMusic(), this sends 2 seconds worth)

ResizeBank(bank,bps) ;Reduce bank fsize to 1/4 of the bytes per second speed

music=PlayMusic(temp_file$) ;Start playing the stream

While ChannelPlaying(music)=1 ;Main loop, repeats while music is still playing
If KeyHit(1) Then End ;End the program if escape is hit
If stream_delay<MilliSecs() Then If Eof(file_in)=0 ;Every 250 milliseconds more data will be written to the output file
If bytes<bps Then a=bytes Else a=bps ;Checks how much can be read
ReadBytes(bank,file_in,0,a) ;Reads bytes from the input file
WriteBytes(bank,file_out,0,a) ;Writes bytes to the output file
bytes=bytes-a ;Subtracts amount moved from byte counter
stream_delay=MilliSecs()+250 ;Waits for 250 milliseconds
p#=100-((Float#(bytes)/Float#(fsize))*100) ;Calculates percentage of file sent
DrawProgress("Streaming... ("+(fsize-bytes)+" of "+fsize+")",p#) ;Update screen
Else
If Not done Then DrawProgress("File fully transfered",100):done=1 ;Displays once the file has been fully transfered for playing
EndIf
Wend

StopChannel music ;Stop music if still playing

CloseFile file_in ;Close input file
CloseFile file_out ;Close output file
DeleteFile temp_file$ ;Delete the tempory file

;Works out wether the sound was fully played or not
Cls
Color 255,255,255
If bytes=0
Text 5,5,"Entire file was streamed succesfully"
Else
Text 5,5,"Only some of the file was streamed, try giving a higher bytes per second value"
EndIf
Flip

FlushKeys()
WaitKey

End

;Draw a progress with description and percentage
Function DrawProgress(t$,p#)
w=GraphicsWidth()
Cls
Color 255,255,255
Text 2,2,t$
Color 255,0,0
Rect 9,20,w-18,16,0
Color 0,150,0
Rect 10,21,(p#/100)*(w-20),14,1
Color 0,0,255
Text w/2,28,Int(Floor#(p#))+"%",1,1
Flip 0
End Function

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