Questions about video dacs/digital modification

[FusionITR]

That's alot of bits to store even for a 640x480 screen. PICs don't have that kind of internal RAM.

Yeah I suppose thats true. I really have to map out how I intend this system to work. I'll get back to you guys with a block diagram when I work that out.

 

[crutschow]

The I/O speed of the PIC is probably less than 20MByte/s.

 

[FusionITR]

Ok guys I have a theory/system design question.

Ok, so say I have a input video signal at 20MHz for simplicity sake (720x480x60), and I have a 10-bit 40MSPS A/D. So I have 10-bit video data clocked out on the A/D going into my DSP every 25ns.

So every 25ns I have new pixel data showing up on my DSP.

Does that mean I have to latch in the new data every 25ns, do whatever processing I want to do to the data and send the data out before I need to latch in the next pixel 25ns later?

If so, thats editing by pixel, what if I wanted it to do by line instead? So I sit and do nothing but latch data in until the line is full, process the line, send out the line, then be ready again all within 25ns? Or am I missing something here?

Also, at what frequency do I need to send out the pixel/line? do I also need to send it out at 40MBps?

From thinking about this it sounds like the DSP has to be MUCH faster than 40MIPs if I want to actually process the data and be ready to store the next sample.

 

[blueroomelectronics]

From thinking about this it sounds like the DSP has to be MUCH faster than 40MIPs if I want to actually process the data and be ready to store the next sample.

You nailed it.

 

[FusionITR]

You nailed it.

Thought so, thanks.

So whats my analysis of store->process->sendout->sample next data functionality of the dsp correct?

 

[blueroomelectronics]

Once more what is the RGB source? What are you trying to do with the signal?

 

[FusionITR]

Once more what is the RGB source? What are you trying to do with the signal?

*Any* generic RGB source with resolutions up to 720x480p.

For example:

A DVD player.
A video game console.
A computer running at 640x480 resolution.

I'm going to be trying some video processing things such as line doubling 240p sources to 480p, de-interlacing 480i signals to 480p. Have overlay menus on top of the video to select options (similar to a regular TV menu), adjust brightness to the source, etc.