Here you will find some tips for capture with ATV2000
in VfW. Enter Capture mode and open Preferences dialog by pressing F10 key.
Here set main parameters:
Video
Video size - set desired video capture resolution, for NTSC maximum
resolution is 640x480 and for PAL 768x576. Some drivers, especially with
BT848/878 chipsets, doesn't provide preview in overlay mode if vertical resolution
is half of max lines or more. In this case turn off preview or switch to
Preview mode.
Encoding - must be set corresponding to desired compressor. Some compressors
works best with YUV modes like MJPEG codecs (use YUY2) and other RGB modes
(for example Indeo). Please be sure that not all capture devices supports
all encoding models. Recommended encodings which offten wors are YUY2 and
RGB24.
Framerate - framerate of video to capture. Typically you should set
it to 25 fps for PAL/SECAM and 29.97/30fps for NTSC.
Video buffers - number of ábuffers used to store video frames. More
buffers can decrease dropped frames on peak performance penalties, but requires
more memory.
Avaliable compressorsá - this is list of avalaible compressors for
current format, but selection has no effect (see below). Select
Open compression
dialog after setup done if you want to open Compression dialog after
pressing OK button.
Preserve video size - check if you want to adjust window to size of
video. In preview mode there will be no stretching.
Hit OK to capture - check if you want to display dialog before capture
starts.
Audio
If you want audio, select audio parameters too. Also you can set number of
Audio buffers like by video.
Audio stream is masterá - the implementation of synchronization is
different then in WDM. Synchronization is done by dropping frames, not by
adjusting framerate in AVI file. Typically there is no need to check this
box.
Compression
Video compression can be set only with standart Windows dialog and cannot
be remembered (so no profiles are implemented in VfW), press F9 to open it
or press Ctrl+F9 to open Audio Compression. After changing video parameters,
compression must be set again, because it is reset to none when changing
encoding. There is one method to store compression, which uses VirtualDub
- it works directly with video samples and passes it to compressor manualy,
not throw VfW interface. If you want to use this method, select VirtualDub
in Options/Application.