QAVI Component

This is a custom component that lets you read and create AVI movie files. AVI stands for audio-video interlace format. You can read 24, 8, or 4-bit color AVI files. However you can only create 24 bit graphics in uncompressed avi format (RLE is ok). Not all AVI files share the same compression, so make sure it is in an uncompressed format. ImageJ is great tool for converting AVI files into uncompressed format.. There is no support for audio yet. Also see video capture by vfw (video for widows)..  See limitations.

QAVI Properties

Field	Type	R/W	Default
bpp	LONG	R/W	24
	Color depth in Bits per Pixel, only 24-bit color is supported for creating AVI files
BytesWritten	LONG	R
	amount of memory written in each frame (equals bitmap size if completed)
Error	STRING	R
	If an error occurs, this will provide a user friendly message..
FileType	STRING	R
	string showing AVI file type header
FirstFrame	LONG	R/W	0
	Frame number of  first video frame, usually is 0
FPS	LONG	R/W
	Frames per second. This is the play-back speed. For MPEG conversion, FPS must be either 10, 12,  15, 24, 25,  or 30
FramesWritten	LONG	R
	when creating an AVI file this keeps track of total output in bytes
Left	LONG	RW	0
Top	LONG	RW	0
Right	LONG	RW
Bottom	LONG       'sets the location of the video in the parent frame. It defaults to QBITMAP for writing.	RW
Height	LONG	R
	Image height of video images, all images should be the same size.
NumFrames	LONG	R/W
	Number of video frames
PaletteRGBQuad	Binary STRING holding the color table (Palette) for 8 and 4 bit video	R
	'get the palette from an AVI PaletteB(255)   AS BYTE PaletteG(255)   AS BYTE PaletteR(255)   AS BYTE DEFINT i, j = 0 FOR i = 0 to 255     PaletteB(i) = ASC(QAVI.PaletteRGBQuad[j])     PaletteG(i) = ASC(QAVI.PaletteRGBQuad[j+1])     PaletteR(i) = ASC(QAVI.PaletteRGBQuad[j+2])     INC(j,4) NEXT i
Quality	LONG	R/W	10000
	image compression quality  from 0 (lowest) to 10000 (highest), only 10000 is currently supported for creating AVI files.
SampleSize	LONG	R
	Frame size in bytes
ShowDialog	INTEGER	R/W
	show windows compression, options dialog box
ShowError	INTEGER	RW	false
	If True error messages will appear with a dialog box automatically
FileType	AS STRING           'string showing AVI file type header	R
CompressionType	AS STRING	R/W
bitPlanes	bitmap bitplanes

QAVI Methods

Method	Type	Description	Params
AVItoBMP	FUNCTION  (AVIFile$, TheBMP AS QBITMAP, FrameNumber%)	Write AVI frame to QBitmap. Pixel Format is set. Returns TRUE on success1
	Bitmaps will be reformated for width and height. Returns TRUE on success
BMPtoAVIFile	FUNCTION (TheBMP AS QBITMAP)	Write bitmap to file, 24 bit only
	Serially stores the bitmap in the AVI file. All bitmaps must be the same size. Returns TRUE on success
CreateAVIFile	FUNCTION (FileName$, Width%, Height%, FramesPerSecond%)	Create an AVI  file to write
	Example: DIM Vid AS QAVI Vid.CreateAVIFile("Custom.AVI",myBMP.Width,myBMP.Height, 15) If sucessful, then the function returns TRUE, and QAVI properties .Width, .Height, .FPS will be reset by the passed parameters
GetAVIFileInfo	SUB (FileName$)	Close AVI file after writing	0
	Read the AVI file and set Properties.  Returns TRUE on success
CloseAVIFile	FUNCTION	Close AVI file after writing	0
	Closes all AVI handles and releases the AVI library memory.  Returns TRUE on success

QAVI Events

Event	Type	Occurs when...	Params
none

QAVI  Examples

'************************************************************************** 
'  Example 1  Read the format of an AVI file
'************************************************************************** 
$INCLUDE <rapidq.inc>
$INCLUDE <QAVI.inc>

DIM myAVI AS QAVI
    myAVI.ShowError = True
    myAVI.GetAVIFileInfo("Test.avi")
    myAVI.CloseAVIFile	'be sure to do this when done

 Showmessage "the file is " + _
         str$(MyAVI.Height) + _
 " x " + str$(MyAVI.Width)  + _
 " , fps = " + str$(MyAVI.fps) + _
 " ,  File type of: " + myAVI.FileType
Application.Terminate

'************************************************************************** 
'  Example 2  Draw your own AVI file
'************************************************************************** 
$INCLUDE <rapidq.inc>
$INCLUDE <QAVI.inc>

DECLARE SUB PaintForm
DIM  i as integer

CREATE TheBMP AS QBITMAP
    Width = 160         'must be on a DWORD (32 bit) boundary
    Height =120
    PixelFormat = pf24bit
END CREATE

CREATE Form AS QFORM
    ClientWidth = TheBMP.Width
    ClientHeight = TheBMP.Height
    OnPaint=PaintForm
END CREATE

CREATE myAVI AS QAVI
    ShowError = True
    NumFrames = 10
END CREATE

' create a new one at 10 frames per second
'properties .Width, .height, .fps will be reset after this function
myAVI.CreateAVIFile("Test.avi", TheBMP.Width, TheBMP.Height, 24, 10)
Form.Show

for i=1 to myAVI.NumFrames
    WITH TheBMP
      .FillRect(0,0, .width, .height, 0)
      .Line(0,0, .width*Rnd, .height*Rnd, &Hff00)
    END WITH
    myAVI.BMPtoAVIFile(TheBMP)
   Form.Repaint
next i
myAVI.CloseAVIFile
Application.Terminate


SUB PaintForm
    Form.Draw(0,0, TheBMP.BMP)
END SUB

'************************************************************************** 
'  Example 3  Get a single frame from an AVI file
'************************************************************************** 
$INCLUDE <Rapidq2.inc>
$INCLUDE <QAVI.inc>

DIM MyAVI AS QAVI
DIM TheBMP AS QBitmapEX

'get the first frame
IF MyAVI.AVItoBMP ("test2.avi", TheBMP, 1) = 0 THEN 
    Showmessage MyAVI.Error
ELSE
    'store it in the system clipboard
    TheBMP.CopyToclipboard
END IF
    MyAVI.CloseAVIFile	'be sure to close the object