the osprey-500 captures video data to the host or to the display device via two different transfer modes. the first mode, odd/even, transfers video such that the odd lines of video are grouped together before the even lines. if the video source was interlaced to start with and the hardware de-interlacing filter was not applied, the odd/even mode basically places the odd field on top of the even field. if the deinterlacing filter was applied (see description further down), this mode places the odd lines of the resultant de-interlaced frame before the even ones. the odd/even transfer mode only occurs when the resolution is greater than half the maximum resolution (]240 for ntsc and ]288 for pal).

    the second mode, interleaved, transfers video vertically in line order. for example, line 1, line 2, line 3, etc. basically, this is an interlaced mode. however, since the video source may have been progressive to start with, or because the de-interlacing filter may have been applied, the term ?(r)interlaced’ transfer mode is inappropriate.

    the following images further describe the odd/even and interleaved transfer modes:

   

    the first image is a snapshot of video captured using the interleaved transfer mode.

    the source is an interlaced dv camera, and the image size is 640x480.

   

    the second image is a snapshot of video captured using the odd/even transfer mode. the source is an interlaced dv camera, and the image size is 640x480.

   

    the third image is a snapshot of video captured using the odd/even transfer mode. the source is an interlaced dv camera, and the image size is 320x480. this mode of capture can be used to acquire video at 60 fields/sec. the osprey-500 already horizontally scaled the video down to 320 pixels in width in hardware. having the 60 fields/sec delivered 30 times a second in the format given here offers the advantage of keeping the odd/even pairing of video consistent in the case of capture loss due to performance of the application.