Amiga was built for this kind of things. An A2000 was my first video post-production equipment.
The video section had external sync inputs that makes external genlock hardware again just a "summing" hardware as amiga was generating its video signals in sync with external video source.
I wonder if one can use the RCA connectors on the A/V expansion board to test this out...
Am I reading it right, that you can capture and show black & white now with P2.
Also, you can capture the color info, but not show it in real time yet?
Yes Amiga was nice to build a genlock. I dream of using a cog like a time base corrector. Scan a tv input with its natural timing and give it out with specific timing that is provided by a external source.
I build this with fpga but it will be a nice project for P2 for long winters
But it is a little of Nonsens too today as analog video is dying
I wonder if one can use the RCA connectors on the A/V expansion board to test this out...
Am I reading it right, that you can capture and show black & white now with P2.
Also, you can capture the color info, but not show it in real time yet?
Yes. The code I posted uses the AV breakout. But it's not optimal. For my testing I use a purpose built board. It has 75 Ohm termination and AC coupling. This way I can use the 3.16x ADC gain mode which has a 1.56Vpp range.
Here is a frame straight from the P2 memory. There are a few interlacing artifacts from not holding the camera perfectly still. The mesh texture is the chroma carrier. Not a P2 artifact.
Hmm it looks like a filter could take care of that chroma mesh artifact without too much trouble
In about 3 weeks the Mars 2020 Perseverance rover launches. From memory is has about 23 cameras on board. It'd be fun to make a model that had 23 cameras, captured using the P2.
Color images from Mars almost seem monochromatic anyway, you'd just need a kind of redder version of 'sepia'
Hmm it looks like a filter could take care of that chroma mesh artifact without too much trouble
In about 3 weeks the Mars 2020 Perseverance rover launches. From memory is has about 23 cameras on board. It'd be fun to make a model that had 23 cameras, captured using the P2.
Color images from Mars almost seem monochromatic anyway, you'd just need a kind of redder version of 'sepia'
Wow, that's a lot of cameras. But they could all be connected to a P2. It couldn't decode all of them at the same time, but it could switch between them with no extra hardware. Color isn't a big problem if we don't need high frame rate.
I have a filter designed for that already. The NTSC standard specified max -2dB @ 1.3MHz, min -20dB @ 3.57MHz. The vertical lines show those limits. This filter fails the first limit by just a tiny bit.
Also, just ran the PC based color decoder on the above image. Overall, I'd say the quality is equal to a slightly noisy analog broadcast.
The P2 is running at 280Mhz, so that means a 280mbps raw data rate. But a bit of that is wasted on the blanking intervals and not filling the full ADC range.
The P2 is running at 280Mhz, so that means a 280mbps raw data rate. But a bit of that is wasted on the blanking intervals and not filling the full ADC range.
Is that one bit per P2 clock or one byte per P2 clock, @SaucySoliton ? Lower case mbps seems to imply bits. I'd hope it was bits otherwise it would be difficult to write at that byte rate into HyperRAM.
The P2 is running at 280Mhz, so that means a 280mbps raw data rate. But a bit of that is wasted on the blanking intervals and not filling the full ADC range.
Is that one bit per P2 clock or one byte per P2 clock, @SaucySoliton ? Lower case mbps seems to imply bits. I'd hope it was bits otherwise it would be difficult to write at that byte rate into HyperRAM.
One bit per clock. That is the rate from the ADC. The data I process is from the scope filter. That downsamples it to 12.273 megabytes per second or 98.184 megabits (rates chosen for square pixels on NTSC). But that could be doubled or quadrupled if using more than one ADC. All the screenshots I've posted are from one ADC.
Gee, for something that never purposely set out to capture analog video, thats mighty useful
Yes, one (or two, sep cog) cameras at a time would be plenty, the P2 could mux which input is active at a time. It would be good to have two for stereoscopic vision.
One bit per clock. That is the rate from the ADC. The data I process is from the scope filter. That downsamples it to 12.273 megabytes per second or 98.184 megabits (rates chosen for square pixels on NTSC). But that could be doubled or quadrupled if using more than one ADC. All the screenshots I've posted are from one ADC.
Great. Then I think we'll be in business for video capture into HyperRAM at decent resolutions that would tax HUB RAM too much, and you could do some post processing from there. For colour decoding it would be ideal to come up with a filter algorithm that can work on bursts read from the HyperRAM into HUB and possibly written back to HyperRAM if needed. Sort of by scanline or groups of lines at a time. I'd imagine that would be how your filter would want to do it anyway, though I'm not much of a DSP guy. I wonder how many COGs will be needed in total for a single NTSC source and at what rate it could process the captured frames?
+1 - I have used a short length of cat5 cable and the standard D 15 pin connectors to connect to an ODROID board (720P) and a Propeller board (1280x1024) to their individual monitors with good results in both cases. Images were sharp, stable, and without artifacts.
Gee, for something that never purposely set out to capture analog video, thats mighty useful
Yes, one (or two, sep cog) cameras at a time would be plenty, the P2 could mux which input is active at a time. It would be good to have two for stereoscopic vision.
The mars 2020 rover has IIRC stereo vision specifically for determining 3D (depth). I’m not sure if curiosity has stereo but I suspect is has too. I’ll have to check.
Posted it: yes, curiosity has stereo cameras on the mast, and low slung stereo cameras for navigation. The 2020 (Perserverance) has more and better cameras as you’d expect for a ~12 years later design.
I've got a fun demo for y'all. How many other microcontrollers can capture FOUR video signals simultaneously? The P2 can.
The program also has the ability to display a single signal at full 640x480 resolution. The image can be displayed on a computer using the debug window. That takes 10 seconds, though.
This is the same functionality as quad processors that were used to monitor security cameras. Devices with this functionality cost $249 back in 1999.
@SaucySoliton said:
I've got a fun demo for y'all. How many other microcontrollers can capture FOUR video signals simultaneously? The P2 can.
The program also has the ability to display a single signal at full 640x480 resolution. The image can be displayed on a computer using the debug window. That takes 10 seconds, though.
This is the same functionality as quad processors that were used to monitor security cameras. Devices with this functionality cost $249 back in 1999.
Nice, Saucy!
How many cogs does it take per channel? Are you ganging ADC pins for faster conversions?
@SaucySoliton said:
I've got a fun demo for y'all. How many other microcontrollers can capture FOUR video signals simultaneously? The P2 can.
The program also has the ability to display a single signal at full 640x480 resolution. The image can be displayed on a computer using the debug window. That takes 10 seconds, though.
This is the same functionality as quad processors that were used to monitor security cameras. Devices with this functionality cost $249 back in 1999.
Nice, Saucy!
How many cogs does it take per channel? Are you ganging ADC pins for faster conversions?
1 cog per channel. I sort of ran out of memory to do more. Theoretically it could go up to 7 channels, then 1 other cog for the display. But going higher would require more downsampling or cropping of the video. Each channel uses about 14k of hub ram to buffer unprocessed samples. I could switch that from longs to bytes to save a bunch. I think it would be possible to run 240x240 from each channel into a 720x480 frame. I had to squeeze some stuff just to be able to debug.
1 pin per channel. It uses the scope filter and streamer to pick off samples at 12.7 MSPS. If I were to use multiple ADCs for the same signal, I would need to add together bytes from within the same long. The cycles to sum 3 or 4 bytes together becomes significant. I felt the video quality was good enough with 1 pin. Applications that need high quality shouid use an external ADC/decoder chip.
This is interesting work Saucy. I wonder if it would be able to write to HyperRAM or PSRAM and read back and display from a frame buffer. What is the total memory bandwidth you need for doing that? I do have the ability to get multiple writers sharing the memory as well as graphics writes that can skip a programmed offset in memory per scanline written so you could put 4 source windows into a common framebuffer.
Comments
https://forums.parallax.com/discussion/92536/propeller-based-video-overlay-osd-module/p1
The video section had external sync inputs that makes external genlock hardware again just a "summing" hardware as amiga was generating its video signals in sync with external video source.
Am I reading it right, that you can capture and show black & white now with P2.
Also, you can capture the color info, but not show it in real time yet?
I build this with fpga but it will be a nice project for P2 for long winters
But it is a little of Nonsens too today as analog video is dying
You don't need to sample the colorburst with the ADC. Just use the counters as an I/Q demodulator, as I laid out here for the P1:
https://forums.parallax.com/discussion/135244/propeller-backpack-color-ntsc-capture/p1
However, without PLLs, you'll have to pick a crystal frequency that gives you 42MHz exactly.
-Phil
Here is a frame straight from the P2 memory. There are a few interlacing artifacts from not holding the camera perfectly still. The mesh texture is the chroma carrier. Not a P2 artifact.
In about 3 weeks the Mars 2020 Perseverance rover launches. From memory is has about 23 cameras on board. It'd be fun to make a model that had 23 cameras, captured using the P2.
Color images from Mars almost seem monochromatic anyway, you'd just need a kind of redder version of 'sepia'
I have a filter designed for that already. The NTSC standard specified max -2dB @ 1.3MHz, min -20dB @ 3.57MHz. The vertical lines show those limits. This filter fails the first limit by just a tiny bit.
Also, just ran the PC based color decoder on the above image. Overall, I'd say the quality is equal to a slightly noisy analog broadcast.
The P2 is running at 280Mhz, so that means a 280mbps raw data rate. But a bit of that is wasted on the blanking intervals and not filling the full ADC range.
Is that one bit per P2 clock or one byte per P2 clock, @SaucySoliton ? Lower case mbps seems to imply bits. I'd hope it was bits otherwise it would be difficult to write at that byte rate into HyperRAM.
One bit per clock. That is the rate from the ADC. The data I process is from the scope filter. That downsamples it to 12.273 megabytes per second or 98.184 megabits (rates chosen for square pixels on NTSC). But that could be doubled or quadrupled if using more than one ADC. All the screenshots I've posted are from one ADC.
Also implied by lower case is millibits per second.
-Phil
Yes, one (or two, sep cog) cameras at a time would be plenty, the P2 could mux which input is active at a time. It would be good to have two for stereoscopic vision.
Great. Then I think we'll be in business for video capture into HyperRAM at decent resolutions that would tax HUB RAM too much, and you could do some post processing from there. For colour decoding it would be ideal to come up with a filter algorithm that can work on bursts read from the HyperRAM into HUB and possibly written back to HyperRAM if needed. Sort of by scanline or groups of lines at a time. I'd imagine that would be how your filter would want to do it anyway, though I'm not much of a DSP guy. I wonder how many COGs will be needed in total for a single NTSC source and at what rate it could process the captured frames?
+1 - I have used a short length of cat5 cable and the standard D 15 pin connectors to connect to an ODROID board (720P) and a Propeller board (1280x1024) to their individual monitors with good results in both cases. Images were sharp, stable, and without artifacts.
The mars 2020 rover has IIRC stereo vision specifically for determining 3D (depth). I’m not sure if curiosity has stereo but I suspect is has too. I’ll have to check.
Posted it: yes, curiosity has stereo cameras on the mast, and low slung stereo cameras for navigation. The 2020 (Perserverance) has more and better cameras as you’d expect for a ~12 years later design.
Then it should be possible to generate a colored overlay !?
I've got a fun demo for y'all. How many other microcontrollers can capture FOUR video signals simultaneously? The P2 can.
The program also has the ability to display a single signal at full 640x480 resolution. The image can be displayed on a computer using the debug window. That takes 10 seconds, though.
This is the same functionality as quad processors that were used to monitor security cameras. Devices with this functionality cost $249 back in 1999.
Nice, Saucy!
How many cogs does it take per channel? Are you ganging ADC pins for faster conversions?
1 cog per channel. I sort of ran out of memory to do more. Theoretically it could go up to 7 channels, then 1 other cog for the display. But going higher would require more downsampling or cropping of the video. Each channel uses about 14k of hub ram to buffer unprocessed samples. I could switch that from longs to bytes to save a bunch. I think it would be possible to run 240x240 from each channel into a 720x480 frame. I had to squeeze some stuff just to be able to debug.
1 pin per channel. It uses the scope filter and streamer to pick off samples at 12.7 MSPS. If I were to use multiple ADCs for the same signal, I would need to add together bytes from within the same long. The cycles to sum 3 or 4 bytes together becomes significant. I felt the video quality was good enough with 1 pin. Applications that need high quality shouid use an external ADC/decoder chip.
Thanks for the explanation, Saucy.
This is interesting work Saucy. I wonder if it would be able to write to HyperRAM or PSRAM and read back and display from a frame buffer. What is the total memory bandwidth you need for doing that? I do have the ability to get multiple writers sharing the memory as well as graphics writes that can skip a programmed offset in memory per scanline written so you could put 4 source windows into a common framebuffer.