[bb] FrameGrabber using AVIFil32.dll by jfk EO-11110 [ 1+ years ago ]

[BlitzBot]

Title : FrameGrabber using AVIFil32.dll
Author : jfk EO-11110
Posted : 1+ years ago

Description : Since a long time I am searching and asking for a fast and reliable way to access frames of an avi. I tried a lot of things and was pretty frustrated in the end. However, wrapping Avifil32.dll for frameaccess only turned out to be less painfull than I thought in the first place.

So here's my version of using Avifil32.dll to access Avi frames.

There are still some Problems with some codecs, especially with the VP6 codec. Any help is welcome to fix this issue.

Code :

Code (blitzbasic) Select Expand

; Approach: Fast and reliable direct Avi Frame access (for Video FX Processing etc.)
; AVIFIL32.DLL is used to read-access certain Frames of an Avi.

; A decls file named Avifil32.decls is required, containing:

;.lib "avifil32.dll"
;AVIFileInit%()
;AVIFileOpen%(ppfile*,szFile$,uMode%,lpHandler%)
;AVIFileRelease%(pfile%)
;AVIFileInfo%(pfile%,pfi*,lSize%)
;AVIFileGetStream%(pfile%,ppavi*,fccType%,lParam%)
;AVIFileExit%()
;AVIStreamStart%(pavi%)
;AVIStreamRelease%(pavi%)
;AVIStreamLength%(pavi%)
;AVIStreamGetFrameOpen%(pavi%,lpbiWanted%)
;AVIStreamGetFrame%(pFrame%,index%)
;AVIStreamGetFrameClose%(pFrame%)

;Additionally in "kernel32.decls" the following lines are required:

;.lib "kernel32.dll"
;RtlMoveMemory2%(Destination*,Source,Length) : "RtlMoveMemory"

;Of course, everything without semicolon.

Graphics 800,600,32,2
SetBuffer BackBuffer()


Const OF_READ=$0

; The following Avi codecs were tested and seem to work without problems:
; HuffYuf
; Indeo 5
; Cinepak Radius
; MPG4 V2


; Some Avi codecs that made troubles:
; DV-Avi: will be detected as not accessible
; VP6n (VP61, VP62 etc.) This one can be accessed, but when the stream and avi is closed,
;      it will produce a Windows Error message that cannot be clicked away until the machine
;      will be rebootet (at least on Win98). Unfortunately it's not possible to detect
;      this problem since Accessing the Frames works, only closing the handles forces the error.
;      I am desperatly seeking for a solution for this issue since it forces the user to
;      manually check the Avi codec before loading to make sure it's not vp6.
;      Any help is welcome!



testfile$="D:videosmoke.AVI"




; **** demo ****

AVIFileInit(); this needs to be called before any other Avifil32.dll function call

; multiple movies may now be opened simultanously, each one gets a bank handle:
avi_struct = bbOpenAvi(testfile$) ; this bank contains useful info. See function bbOpenAvi
; if it's zero then our app failed to open the avi sor some reason:
If avi_struct=0 Then
 AVIFileExit()
 RuntimeError "error opening avi "+testfile$
Endif

FirstFrame1=PeekInt(avi_struct,136)
NumFrames1 =PeekInt(avi_struct,140)

index1=FirstFrame1

ClsColor 50,50,50
While KeyDown(1)=0
  img=bbAviGetFrame(avi_struct,index1)
  Cls
  DrawBlock img,10,10
  FreeImage img
  Text 100,100,"Frame: "+index1+"  "
  Flip
  index1=index1+1
  If index1>=NumFrames1 Then index1=FirstFrame1
Wend

If avi_struct <> 0 Then
 bbCloseAvi(avi_struct) ; don't forget this!
EndIf

AVIFileExit()          ; this needs to be called  here to release the avifil32.dll initialisation !
End







; **********************************************************************************************
Function bbOpenAvi(file$)
 ; After opening the avi file we will need to retrieve some info from the avi handler.
 ; the following structure will be used:
 ; AVIFILEINFO structure:
 ;    0 dwMaxBytesPerSec;
 ;    4 dwFlags;
 ;    8 dwCaps;
 ;   12 dwStreams;
 ;   16 dwSuggestedBufferSize;
 ;   20 dwWidth;
 ;   24 dwHeight;
 ;   28 dwScale;
 ;   32 dwRate;
 ;   36 dwLength;
 ;   40 dwEditCount;
 ;   44 string  szFileType 64 bytes;
 ; (11*4)+64 =108
 ; size of AVIFILEINFO structure: 108 bytes
 s=108
 ; create a bank that A) stores the AVIFILEINFO that is given by Avifil32.dll, and B) store
 ; some bank handles, avifile handles, stream handles, frame handles that will be used
 ; in other functions as well. In case of B) the Data is stored at offset 128 and higher.
 AviFileInfoBank=CreateBank(512)
 For i=0 To 508 Step 4
  PokeInt AviFileInfoBank,i,0
 Next

 ret=CreateBank(8) ; will hold the avifileopen handle
 res=AVIFileOpen(ret,file$,OF_READ,0)
 avi_handle=PeekInt(ret,0)
 If res<>0 Then ; error opening!
  If avi_handle<>0
   AVIFileRelease(avi_handle)
  EndIf
  FreeBank ret
  FreeBank AviFileInfoBank
  Return 0
 EndIf
 ;Print "opened file" ; used for debugging purposes

 ;*** GET AVI INFO ***
 res=AVIFileInfo(avi_handle,AviFileInfoBank,108)
 ; string "szFileType", 64 bytes, contains some info about the Avi handler (well not used here, but, anyway)
 szFileType$=""
 For i=44 To 108
  If PeekByte(AviFileInfoBank,i)=0 Then Exit
  szFileType$=szFileType$+Chr$(PeekByte(AviFileInfoBank,i))
 Next
 ;Print "got info" ; used for debugging purposes
 ;Print szFileType$

 PokeInt AviFileInfoBank,128,avi_handle ; store avi_handle for future usage


 ;*** Open AVI STREAM ***
 ; fccType is a 32Bit long string that may be:
 ; "vids","auds","mids" or "txts" (of course we only use "vids")
 ; sent as 32 bit unsigned long:
 ; 1935960438 vids
 ; 1935963489 auds
 ; 1935960429 mids
 ; 1937012852 txts
 fccType=1935960438
 res=AVIFileGetStream(avi_handle,ret,fccType,0)
 stream_handle=PeekInt(ret,0)

 If res<>0 Then ; error getting stream!
  If stream_handle<>0
   AVIStreamRelease(stream_handle)
  EndIf
  If avi_handle<>0
   AVIFileRelease(avi_handle)
  EndIf
  FreeBank ret
  FreeBank AviFileInfoBank
  Return 0
 EndIf
 ;Print "got stream" ; used for debugging purposes

 PokeInt AviFileInfoBank,132,stream_Handle ; store stream_handle for future usage

 FirstFrame=AVIStreamStart(stream_handle)
 If firstframe<0 Then ; signs of incorrect avi data (no frames)
  If stream_handle<>0
   AVIStreamRelease(stream_handle)
  EndIf
  If avi_handle<>0
   AVIFileRelease(avi_handle)
  EndIf
  FreeBank ret
  FreeBank AviFileInfoBank
  Return 0
 EndIf
 ;Print "firstframe >-1" ; used for debugging purposes

 NumFrames=AVIStreamLength(stream_handle)
 If numframes<=0 Then ; no frames in avi
  If stream_handle<>0
   AVIStreamRelease(stream_handle)
  EndIf
  If avi_handle<>0
   AVIFileRelease(avi_handle)
  EndIf
  FreeBank ret
  FreeBank AviFileInfoBank
  Return 0
 EndIf
 ;Print "numframes > 0" ; used for debugging purposes

 PokeInt AviFileInfoBank,136,FirstFrame ; store FirstFrame for future usage
 PokeInt AviFileInfoBank,140,NumFrames ; store NumFrames for future usage



 frame_handle=AVIStreamGetFrameOpen(stream_handle,0) ; 0= default, 1=bestdisplay
 If frame_handle=0 ; failed to create a frame access handle
  If stream_handle<>0
   AVIStreamRelease(stream_handle)
  EndIf
  If avi_handle<>0
   AVIFileRelease(avi_handle)
  EndIf
  FreeBank ret
  FreeBank AviFileInfoBank
  Return 0
 EndIf
 PokeInt AviFileInfoBank,144,frame_handle ; store frame_handle for future usage
 ;Print "frame handle <> 0" ; used for debugging purposes

 ; create a bank that will be used to store the DIB bitmaps delivered by "AviStreamGetFrame".
 ; (currently only 24 bit DIB mode is supported)
 FrameBank=CreateBank((PeekInt(AviFileInfoBank,20)*PeekInt(AviFileInfoBank,24)*3)+40+1000)
 PokeInt AviFileInfoBank,148,FrameBank ; store FrameBank for future usage
 FreeBank ret
 Return AviFileInfoBank
End Function








Function bbAviGetFrame(AviFileInfoBank,index) ;request a certain frame and move the DIB image to a bank
 frame_adress=AVIStreamGetFrame(PeekInt(AviFileInfoBank,144),index)
 RtlMoveMemory2(PeekInt(AviFileInfoBank,148),frame_adress,40+(PeekInt(AviFileInfoBank,20)*PeekInt(AviFileInfoBank,24)*3))
 img=decodeDIB(PeekInt(AviFileInfoBank,148),PeekInt(AviFileInfoBank,20),PeekInt(AviFileInfoBank,24))
 Return img
End Function



Function bbCloseAvi(AviFileInfoBank) ; close frame, stream, avi, release used banks
 AVIStreamGetFrameClose(PeekInt(AviFileInfoBank,132))
 AVIStreamRelease(PeekInt(AviFileInfoBank,132))
 AVIFileRelease(PeekInt(AviFileInfoBank,128))
 FreeBank PeekInt(AviFileInfoBank,148)
 FreeBank AviFileInfoBank
End Function




Function decodeDIB(bank,w,h) ; create an image from a 24bit DIB image stored in a bank
 img=CreateImage(w,h)
 SetBuffer ImageBuffer(img)
 LockBuffer ImageBuffer(img)
 z=40
 For y=0 To h-1
  For x=0 To w-1
   rgb=PeekInt(bank,z) And $FFFFFF
   WritePixelFast x,(h-1)-y,rgb
   z=z+3
  Next
 Next
 UnlockBuffer ImageBuffer(img)
 SetBuffer BackBuffer()
 Return img
End Function

Comments :


Litobyte(Posted 1+ years ago)

 Would be hard to the same for videocap ?One of the greatest lack of blitz3D is the ability to grab from a directshow device.All what I have seen working, was dead slow, it will be sweet to be able to process images for analysis coming from a camera.This will open blitz3D to a lot of gaming ( playing in front of a cam ) and tools possibilities.


ZJP(Posted 1+ years ago)

 Hi,This does not work with the Xvid codec.JP