While 900 kBytes will fit many times over into the RAM of a Raspberry Pi 400, the Pico only has 264KB RAM.Īs you see, we will need to reduce some of the parameters (e.g. This needs to be RAM, since we are operating at high speeds, and need to be able to read this reliably with small latencies – which Flash memory would not provide.
#Lakka raspberry pi 3 sound via hdmi update#
To output this information, ideally you would also want to hold this information as a bitmap in your RAM – one part of your application will update the image in the RAM, while another will take care of delivering the data in a format which a monitor can work with. (Consider that for example the USB v1.1 interface on the Pico has about 10 Mbit/s – about 40 times less throughput!)
![lakka raspberry pi 3 sound via hdmi lakka raspberry pi 3 sound via hdmi](https://images.ctfassets.net/2lpsze4g694w/1BasKZCgPekbfHy0Df5moL/484976c0c7cf496c7ca802cd067fb494/Blade-Buster.png)
Let’s calculate how much data this is per second: ideally about 60 different values per second (60 Hz).Adding red to green yields yellow, adding green to blue yields cyan, adding blue to red yields magenta. When you add all three of them, you get white. You’ve probably heard about these colors before:
![lakka raspberry pi 3 sound via hdmi lakka raspberry pi 3 sound via hdmi](https://res.cloudinary.com/practicaldev/image/fetch/s--RBbR-YLW--/c_imagga_scale,f_auto,fl_progressive,h_1080,q_auto,w_1080/https://www.raspberrypi.org/app/uploads/2017/05/Raspberry-Pi-3-1-1619x1080.jpg)
(On a sidenote, purple does not really exist as it’s own wavelenght – it’s a mixture of red and blue). Again, our brain will synthesize the colors inbetween from this information it gets. We have three different photoreceptors for color, so the screen displays only these three different colors with different brightness. Of course, we want these pictures to be in color. Our brain will interpret these static pictures as smooth and life-like playback.
![lakka raspberry pi 3 sound via hdmi lakka raspberry pi 3 sound via hdmi](https://cdn.retrorgb.com/wp-content/uploads/2020/04/20171051/RPi3bCompositeVideoMod-scaled.jpg)
(which is about 1 in 75 frames per second).įor us this means, if we want to display a really smooth animation, we need to show about 60 different static pictures per second. The brain, however has latencies – it is not able to resolve changes in visual stimuli faster than 13 ms. Look into bipolar cells if you’re interested to know more) (* the mechanism of transmission into the brain integrates information across several retina cells, but the fact remains that a lot of information is transmitted in parallel. a cat with a butterfly, an example of what we want to show to our users. Our brain has massively parallel wiring, in which it ingests information from all available retina cells at once (cone cells and rod cells).
![lakka raspberry pi 3 sound via hdmi lakka raspberry pi 3 sound via hdmi](https://user-images.githubusercontent.com/33697235/83955023-a0e2f300-a81c-11ea-9ffa-63afa53bc8cc.jpg)
We see the display on the screen “at once”. To understand this better we need to look at some fundamentals of computer video output: Video display and transmission It also has a massive memory (of 4 GB), in which to store the video output data. This system-on-a-chip has specialized hardware which takes care of the video output, perfectly preparing it in the format which is specified for the particular video interface(s), two HDMI ports in the case of the Pi 400. The Raspberry Pi 400, for example, is based on the BCM2711 SoC. If you’ve succeeded doing your own video project with the Raspberry Pi Pico, let us know in the comments :-)! Why is adding a Raspberry Pi Pico Video output a challenge? Do you recognize the face? Let us know in the comments Pico Video output using the DVI sock – wild animations are possible.