1080p input/output on Artix-7

[hamster_nz]

I've managed to get DVI-D 1080p to pass through an Artix-7 FPGA - it is a bit out of spec for the chip (about 30% 'overclocked' for the SERDES modules, and about 25% for the fastest clock network in the design), but does work pretty well for experimentation.

My code is at http://hamsterworks.co.nz/mediawiki/index.php/Artix_7_1080p_passthrough if you are interested in toying with it...

[electro-logic]

NexysVideo isn't thinked for video application? Why do you have to go out of specs for HDMI?

[hamster_nz]

Why do you have to go out of specs for HDMI?

I guess they were aiming at 720p and 1080i. The HDMI isn't hooked to high-speed transceivers (only the DisplayPort is), so even for the fastest grade FPGA, the SERDES is only rated at around 1,250 Mb/s (where 1080p needs 1,485 Mb/s). Also for the fastest grade, the I/O clock buffers (BUFIO) are rated at 680MHz, but this needs 750MHz.

And I think the board has a slower -1 grade on it....

[slateraptor]

Why do you have to go out of specs for HDMI?

I guess they were aiming at 720p and 1080i. The HDMI isn't hooked to high-speed transceivers (only the DisplayPort is), so even for the fastest grade FPGA, the SERDES is only rated at around 1,250 Mb/s (where 1080p needs 1,485 Mb/s). Also for the fastest grade, the I/O clock buffers (BUFIO) are rated at 680MHz, but this needs 750MHz.

And I think the board has a slower -1 grade on it....

Can you run through really quick how you came up with your bandwidth estimate? I'm def getting a figure appreciably lower than ~1485 Mbps:

Assuming 60 fps @ ~5% reduced blanking, I'm getting:
(1920 x 1080 x 60 x 10 x 1.05) / 2²⁰ ~= 1246 Mbps

I would imagine handling 1080p/24 should be without issue.

[hamster_nz]

Can you run through really quick how you came up with your bandwidth estimate? I'm def getting a figure appreciably lower than ~1485 Mbps:

Assuming 60 fps @ ~5% reduced blanking, I'm getting:
(1920 x 1080 x 60 x 10 x 1.05) / 2²⁰ ~= 1246 Mbps

I would imagine handling 1080p/24 should be without issue.

It wasn't so much about generating 1080p, but accepting 1080p from a standard source (so I can play around with the video).

SMTPE 1080p@60 (which is what I am expecting a source to supply - e.g. a generic media player) is 2200 counts per line, 1125 lines per frame, 60 frames per second. As TMDS uses an 8b/10b coding scheme, it needs 2200×1125×60×10 = 1,485 Mb/s

Or perhaps simpler, the standard 1080p pixel clock is 148.5 MHz so the per channel bit rate is 1,485 Mb/s, on each of the three channels (for 24 bits per pixel colour depth)

[electro-logic]

Uff.. always the slower grade..