OSD Updating and Timing. DM6437 (Using DSP/BIOS)
We are considering using the OSD to overlay a drawing on a 30 fps video output.
The image overlay will persist for 3 or more frames then get updated with a new overlay.
The OSD HW does not support ping-pong Addresses. (I assume that the ping-pong feature is how the FVID_exchange driver function seamlessly switches between window's for VIDWIN0.)
1. Can I still use FVID_exchange() with OSDWIN0?
1.a. If not, how should I update the content. (i.e., memcopy)
1.b. Could I introduce my own ping pong by enabling and disabling OSD0/OSD1?
1.c Without the Ping /Pong buffer, how can I minimize any glitches due to timing such as tearing (i.e., updating the OSD data while it is being displayed) or displaying dual overlays from OSD0 and OSD1 when enabling / disabling.
2. Is there some synchronization between OSD windows with VIDWIN0?