Return second field offset for interlaced modes (1080i only for now).

[bmusb] / bmusb.h

diff --git a/bmusb.h b/bmusb.h
index 2ed7308648f3df399b7fca778a22d42015461af9..d47ce8e85c4541be65dcd89c7b10ed727781b153 100644 (file)
--- a/bmusb.h
+++ b/bmusb.h
@@ -157,8 +157,11 @@ class BMUSBCapture {
 
 // Get details for the given video format; returns false if detection was incomplete.
 // Note: Frame rate is _frame_ rate, not field rate. So 1080i60 gets 30/1, _not_ 60/1.
-// TODO: Add another extra_lines_ parameter for interlaced.
-bool decode_video_format(uint16_t video_format, unsigned *width, unsigned *height, unsigned *extra_lines_top, unsigned *extra_lines_bottom,
+// "second_field_start" is only valid for interlaced modes; it signifies
+// how many lines from the very top of the frame there are before the second field
+// starts (so it will always be >= height/2 + extra_lines_top).
+bool decode_video_format(uint16_t video_format, unsigned *width, unsigned *height, unsigned *second_field_start,
+                         unsigned *extra_lines_top, unsigned *extra_lines_bottom,
                          unsigned *frame_rate_nom, unsigned *frame_rate_den, bool *interlaced);
 
 #endif