posts tagged with the keyword ‘raspberrypi’

2018.08.26

low-res-video

For the past few years I’ve been creating weird videos that (often) celebrate retro-computing with modern day low-power computing by making a Raspberry Pi connected to an old Apple display monitor play videos. You may remember Apple Watch and Apple Wait from past years of Maker Faire Milwaukee.

I’ve struggled a bit with the process of using modern software to create low-resolution videos, and I’m sure there is more than one way to do it, but I thought I’d document my process so that the next time I do it I’ll have a simple guide to follow. I’m calling this my “Guide to creating Standard Definition Video files for Raspberry Pi”.

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When I create a new video file in Final Cut Express (yeah, I’m still using it) I just pretty much assume I’ll want an HD version, so that’s what I create, even if I plan to have a standard definition video as my final output. Video files get created at 1920×1080, also known as “1080″, for short. Let’s make a 1920×1080 file in Photoshop.

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Our final file will be 640×480, but since SD is 4:3 versus HD which is 16:9, we need to adjust for that. If we put in 480 for the height of the file, we see it proportionally scales down the width to 853. (I remember this number from my video editing days!)

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853 isn’t what we want… we want 640, so subtract 640 from 853 and what do you get? Well, it’s 213. Maths, duh! (Remember, we’re going from 16:9 to 4:3 aspect ratio, so we need to lose some of the image.)

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Divide that 213 in half and we get 106.5, but since we need an integer and not a floating point, we will use two numbers, 107 and 106. Those are the number of pixels we need to crop from our video file.

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I still use MPEG Streamclip because, wow, it’s awesome and it works. I’ve highlighted all the important settings I need to care about. We are loading in our full HD (1080) video file, and then scaling it down to 853×480 and also cropping it, 107 pixels on the left, and 106 pixels on the right. (Selecting “Deinterlace Video” can help too, depending on the look you want.)

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If the export preview from MPEG Streamclip looks wrong, you probably did something wrong. If it looks right, then you are probably in luck! Once your MP4 file is saved, you can check it out.

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I open it with QuickTime Player to check the resolution. It’s 640×480, so everything is good. So now I’ve got a Standard Def 640×480 MP4 video file that is all set to be played on a Raspberry Pi connected via composite video to an old fashioned 4:3 video display.

2017.05.14

Les Yeux

One of the pieces I displayed at Maker Faire Milwaukee in 2016 consisted of two monitors showing a pair of eyes. I was (slightly) inspired by Ben’s Video Wall of Terror.

Les Yeux

I started by filming Dr. Prodoehl to capture the movement of her eyes. The crop lines show where I planned to crop the single video into two separate videos. I also used filters on the videos to get the old TV scan line effect and add a bit of distortion. (The cropping is for a 4:3 aspect ratio display to be compatible with the old computer monitors I had on hand.)

Les Yeux

The two videos were then exported and one was trimmed to be about a half second shorter than the other one. Since the installation would be running for two full days this meant that we’d see some interesting time drifts between the two videos.

The videos were played using a pair of Raspberry Pi Zero single board computers. Like nearly every installation, there were problems involving technology, this time I think it was a bad SD card, but I quickly swapped it out and got up and running again.

Here’s a short video showing Les Yeux Times at Maker Faire in 2016, along with the two videos that were used.

2017.04.09

Apple Wait...

At Maker Faire Milwaukee in 2015 I presented a piece titled Apple Watch, and at least one person enjoyed it enough to make me think about creating another piece utilizing the same concept, so for Maker Faire Milwaukee 2016 I presented Apple Wait….

Apple Wait...

Apple Wait… (like Apple Watch) consisted of a Raspberry Pi Model B connected to an Apple Monochrome Monitor from 1988. Instead of just attaching the Raspberry Pi to the monitor with some gaff tape, I added in one more reference to technology, an iPhone box.

Apple Wait...

It seems the box for an iPhone is just the right size to house a Raspberry Pi Model B. Interesting enough, the iPhone 4S and the Raspberry Pi Model B were released about the same time frame. They are very different devices, with different goals, aimed at different audiences. Why not merge the two together? Technology is interesting!

Apple Wait...

For Apple Wait… I took a busy indicator cursor from the olden days of computing on Apple devices and brought it into the modern day, but made it 8-bit and low-rez, because retro is in. If you’re interested in learning more about old things, check out Where did the loading spinner originate?, The Design of Spinning Indicators, Spinning pinwheel, History of the Mac Spinning Wait Cursor, and just for a laugh, The Marble of Doom.

Apple Wait...

2017.03.13

MMS WebCam

It’s been way too long since I posted anything about the Time Lapse Bot project. Here’s some good background info, if needed.

Time Lapse Bot 3, which I haven’t written about since 2011 (or maybe 2012) has seen a few upgrades. Don’t worry, it’s still running an ancient PowerBook G4 (how, I don’t even know) but we long ago upgraded to a Logitech C910 USB camera. We then added a long gooseneck to allow for easy adjust-ability. And finally, it’s also known as the Milwaukee Makerspace Webcam, and it published views of Milwaukee Makerspace at http://mkemake.us/webcam

But really, Time Lapse Bot 3 hasn’t changed very much in the past few years… probably because I’ve been working on Time Lapse Bot 4, which uses a Raspberry Pi.

tlbot4

Time Lapse Bot 4.01 made an appearance at Maker Faire Milwaukee in 2016, using a completely hacked together frame on one of my old rolling chair bases, and it worked for the weekend, but I’ve got plans… I’ve got plans.

I’ve made a lot of progress with software, and picamera is something I highly recommend! I’ve also got TLBot4 automagically uploading to a server, just like the Milwaukee Makerspace Webcam (running EvoCam, which may be dead now, as the web site of the developer has gone AWOL) and it’s also doing the daily videos compiled from the still images. I’m 90% happy with the software… I mean, the last 10% is the hardest, right?

I’m also working on a new physical build of Time Lapse Bot 4, which will feature many mounting solutions, and an interchangeable wide angle lens for capturing crowds.

Hopefully I can get TLBot 4 up and running for an event in the next few months, but in the meantime, I’ll be testing it in my workshop. (And hey, it’s offline now, so what the heck!?)

Also, I used the knowledge and experience I’ve gained (especially from picamera) to create part of a museum exhibit that has been running trouble-free (knock on HDPE!) since November. Huzzah!

2016.12.14

T35TP4TT3RN

T35TP4TT3RN (aka TEST PATTERN) is a piece I created for Maker Faire Milwaukee in 2016. It consists of a Raspberry Pi single board computer connected to an old Sony broadcast monitor. (I got the monitor from another member of Milwaukee Makerspace who was getting rid of old equipment.)

T35TP4TT3RN

As I often do, I wanted to contrast old hardware with modern hardware. I ended up using a Raspberry Pi Model B which has composite video out via an RCA jack. I used an RCA to BNC adapter to connect to the monitor. The display is a whopping 640×480 pixels.

T35TP4TT3RN

I used the Raspberry Pi Slideshow technique and with most installations, I tried to do a good amount of testing beforehand, letting it run for days at a time. I came across an issue where the system would freeze, and it would get stuck on an image. I contemplated switching to display of a video, but really wanted to avoid that, so I set a cron job to reboot the Pi every 30 minutes. I figured that if someone saw the screen during reboot it would be an extra BTS sort of treat. (The Pi boots very fast.)

T35TP4TT3RN

I did end up altering the monitor a bit. I removed the case and broke out a bit of the battery compartment so I could slide the Pi and extra cable into the battery slots. Since I’ll probably never own the batteries for this unit, hacking it seemed like a no-loss situation.

Here’s a collection of a few of the test patterns that were displayed.

T35TP4TT3RN

T35TP4TT3RN

T35TP4TT3RN

T35TP4TT3RN

T35TP4TT3RN

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