VideoLib Pro OCX
Application Programming Interface
Properties | Methods | Events
Index
General
General component properties.
Capture Parameters
These properties set the parameters for capturing video.
Audio Parameters
These properties set the parameters for audio.
Colors
Sets the colors that will be used.
Active
Value
Boolean
Purpose
Turns the video capture window on and off. Setting this
property to True will cause VideoLib OCX™ to load the
AVI drivers into memory and connect to the video capture
card. A False value will unload all of the video drivers.
Example
{ Turn on video window }
videolib.Active := True;
AVIAllocate
Value
Long
Purpose
This property will pre-allocate the size of the file
specified in AVIFileName before beginning a video capture
Sequence. Pre-allocating a file can increase the efficiency
of the capture session. This can also cause wasted space, if
the capture session does not use all of the space allocated.
The capture Sequence will automatically extend the file if
necessary. A value of zero will cause the program to use the
size of the file currently allocated. To insure a new empty
file, this value can be set to one.
Example
{ Force AVI file to be recreated on each sequence call }
videolib.AVIAllocate := 1;
AVIFileName
Value
BSTR
Purpose
This is the file path and name of the AVI file. The data in
this file will be over-written on each call to Sequence.
Example
{ Turn on video window }
videolib.Active := True;
Overlay
Value
Boolean
Purpose
Allows live video to be displayed within a window. The video
will be shown when Active is set to True. The video is
displayed to the control using hardware overlay. Using
Overlay does not require CPU resources. Enabling Overlay mode
automatically disables Preview mode.
Example
{ Turn on video window }
videolib.Active := True;
Preview
Value
Boolean
Purpose
Allows live video frames to be previewed within a window. The
video will be shown when Active is set to True. In this mode,
frames are transferred from the capture hardware to system
memory and then displayed in the capture window using GDI
functions. Enabling Preview mode automatically disables
Overlay mode.
Example
{ Turn on video window }
videolib.Active := True;
PreviewRate
Value
Short
Purpose
Rate in milliseconds at which new frames are captured and
displayed. Preview mode takes up massive CPU resources.
Applications should increase this value, whenever possible,
to allow other applications to run.
Example
{ Set the preview rate to 10 frames per second }
videolib.PreviewRate := 100;
videolib.Preview := True;
Scale
Value
Boolean
Purpose
When enabled, the captured video frame is stretched to the
dimensions of the capture window. Some video capture boards
only support a multiple of 40x30 in Overlay mode. For these
boards videolib OCX™ will automaticlly scale the window
down to the closest size.
Example
{ Enable scaling }
videolib.Scale := True;
VideoDriver
Value
Short
Purpose
This is the integer value of the video driver.
Example
{ Set video driver to the first capture board }
videolib.VideoDriver := 0;
VideoSize
Value
BSTR
Purpose
This property sets the size of the video window in Overlay
mode. This is only if Scale is set to False. The string
representing the video window size should be formated in the
following manner: WIDTHxHEIGHT.
Example
{ Set video window to 280 width by 210 height }
videolib.Scale := False;
videolib.VideoSize := ‘280x210’;
AbortLeftMouse
Value
Boolean
Purpose
If set to True, the video capture Sequence will stop when the
user presses the left mouse button.
Example
{ Allow user to end capture with left or right mouse button }
videolib.AbortLeftMouse := True;
videolib.AbortRightMouse := True;
AbortRightMouse
Value
Boolean
Purpose
If set to True, the video capture Sequence will stop when the
user presses the right mouse button.
Example
{ Allow user to end capture with left or right mouse button }
videolib.AbortLeftMouse := True;
videolib.AbortRightMouse := True;
ChunkGranularity
Value
Long
Purpose
Logical block size, in bytes, of the AVI file. The value 0
indicates the current sector size is used as the granularity.
Audio and video chunks will have junk chunks appended to
round the chunk up to the next multiple of ChunkGranularity.
Example
{ Set the chuck size to the default sector size }
videolib.ChunkGranularity := 2048;
DisableWriteCache
Value
Boolean
Purpose
Disables the memory to disk cache. This parameter should be
set to False, it is included only for compatibility.
Example
videolib.DisableWriteCache := False;
IndexSize
Value
Long
Purpose
Maximum number of index entries allowed in the AVI file. If
set to zero, a default value of 32K is used. Each video frame
uses one index entry. Values range from 1,800 to 324,000.
Example
{ Set maximum number of indexes allowed }
videolib.IndexSize := 0;
KeyAbort
Value
Short
Purpose
Virtual key code to use as an abort to the capture Sequence.
Example
{ Set abort key to ESCAPE }
VideoCaptureParms.KeyAbort := 27;
MakeUserHitOKToCapture
Value
Boolean
Purpose
When set to True, this property displays a dialog box
requesting the user to hit OK when ready to begin the video
capture Sequence.
Example
{ Display ‘Hit OK’ dialog }
videolib.MakeUserHitOKToCapture := True;
videolib.Sequence();
MCIControl
Value
Boolean
Purpose
If True, the capture window controls a MCI-compatible video
source during streaming capture. MCI-compatible video sources
include VCRs and laserdiscs.
Example
videolib.MCIControl := False;
MCIStartTime
Value
Long
Purpose
Starting position of the MCI device for the capture sequence.
Time is in milliseconds. This field is ignored if MCIControl
is set to False.
Example
videolib.MCIStartTime := 0;
MCIStopTime
Value
Long
Purpose
Stopping position of the MCI device for the capture sequence.
Time is in milliseconds. This field is ignored if MCIControl
is set to False.
Example
videolib.MCIStopTime := 0;
NumVideoRequested
Value
Long
Purpose
Specifies the maximum number of video buffers to allocate.
The memory area used for the buffers is determined by the
UsingDOSMemory flag. The actual number of buffers allocated
might be lower if memory is unavailable. The default number
of buffers allocated is 3 and the maximum is 1000.
Example
videolib.NumVideoRequested := 3;
PercentDropForError
Value
Long
Purpose
Maximum percentage of dropped frames during a capture
Sequence. The capture will be aborted if the number of
dropped frames falls outside of this percentage. Values range
from 0 to 100.
Example
{ Abort if more than 20 percent for the frames are dropped }
videolib.PercentDropForError := 20;
StepMCIDevice
Value
Boolean
Purpose
If True, step capture using a MCI device as a video source is
enabled. Otherwise, real-time capture using an MCI device is
enabled. This field is ignored if MCIControl is set to False.
Example
videolib.StepMCIDevice := False;
TimeLimit
Value
Long
Purpose
Maximum number of seconds to capture. Only used if
TimeLimitEnabled is set to True.
Example
{ End capture after 10 seconds }
videolib.TimeLimitEnabled := True;
videolib.TimeLimit := 10;
TimeLimitEnabled
Value
Boolean
Purpose
If set to True, capture Sequence will terminate after
TimeLimit seconds.
Example
{ No time limit }
videolib.TimeLimitEnabled := False;
RequestMicroSecPerFrame
Value
Long
Purpose
Requested frame capture rate, in microseconds. The default
value is 66667, which corresponds to 15 frames per second.
This value represents the number of microseconds between
successive frames.
Example
{ Set the capture rate to 30 frames per second }
videolib.RequestMicroSecPerFrame := 1000000 / 30;
StepCaptureAt2x
Value
Boolean
Purpose
If set to True, the capture hardware captures at twice the
specified resolution. Enable this option if the hardware does
not support hardware-based decimation and you are capturing
in the RGB format.
Example
{ Capture the video at twice the display size }
videolib.StepCaptureAt2x := True;
StepCaptureAverageFrames
Value
Long
Purpose
Number of times a frame is sampled when creating a frame
based on the average sample. This averaging technique reduces
the random digitization noise appearing in a frame.
Example
{ Use 5 samples for one frame }
videolib.StepCaptureAverageFrames := 5;
UsingDOSMemory
Value
Boolean
Purpose
In Windows 3.1, a True value will attempt to allocate capture
buffers in the memory area below one megabyte. This value is
not used in 32-bit applications, but is included here for
compatibility.
Example
videolib.UsingDOSMemory := False;
Yield
Value
Boolean
Purpose
If this value is set to True, the capture process is
performed in a separate thread. Applications which use this
feature must support re-entry issues.
Example
{ Block the user during a sequence call }
videolib.Yield := True;
AudioBufferSize
Value
Long
Purpose
Size of audio buffers. If zero is used, the size of each
buffer will be the maximum of 0.5 seconds of audio (10K
bytes).
Example
{ Set to the maximum }
videolib.AudioBufferSize := 0;
AVStreamMaster
Value
Long
Purpose
If set to 0, the audio stream controls the clock when writing
an AVI file. This gives higher priority to writing audio over
video. If set to 1, the duration of audio and video streams
can differ.
Example
{ Give priority to the audio stream }
videolib.AVStreamMaster := 0;
BitsPerSample
Value
Short
Purpose
The number of bits per sample. Should be 8 or 16.
Example
{ 8 bits per sample }
videolib.BitsPerSample := 8;
CaptureAudio
Value
Boolean
Purpose
If set to True, audio is captured during the capture
Sequence.
Example
{ Disable audio for a smaller AVI file }
videolib.CaptureAudio := False;
Channels
Value
Short
Purpose
Number of audio channels. (1-Mono, 2-Stereo).
Example
{ Set to mono to save on disk space }
VideoAudioParms.Channels := 1;
FormatTag
Value
Short
Purpose
Waveform-audio format type. Default format type is
WAVE_FORMAT_PCM (1).
Example
videolib.FormatTag := 1;
NumAudioRequested
Value
Long
Purpose
Maximum number of audio buffers to use. The size of each
buffer is the maximum of 0.5 seconds of audio or 10K bytes.
Maximum value is 10.
Example
videolib.NumAudioRequested := 10;
SamplesPerSec
Value
Long
Purpose
Sample rate, in samples per second (hertz), that each channel
should be played or recorded. Common values are 8.0 kHz,
11.025 kHz, 22.05 kHz, and 44.1 kHz.
Example
{ Set sample rate to 11.025 kHz }
videolib.SamplesPerSec := 11025;
BackColor
Value
Long
Purpose
Sets the background color for the videolib OCX™. This
is a RGB value.
Example
{ Set the back ground to black }
videolib.BackColor := 0;
Back to Home
SkyLine Tools Imaging
A division of Creative Development, Ltd.
For sales and additional info, send E-Mail to sales@imagelib.com
or contact SkyLine via Phone (818) 585-5867
© 1994 - 2002 SkyLine Tools Imaging. All rights reserved.