Explore FFmpeg From The Comfort Of Your Browser

August 27, 2023 by Tom Nardi 24 Comments

If you’re looking to manipulate video, FFmpeg is one of the most powerful tools out there. But with this power comes a considerable degree of complexity, and a learning curve that looks suspiciously like a brick wall. To try and make this incredible tool a bit less obtuse, [Sam Lavigne] has developed a web interface that lets you play around with FFmpeg’s vast collection of audio and video filters.

To try out a filter, you just need to select one from the window on the left and it will pop up in the central workspace. Here, the input, output, and any enabled filters will show up as boxes that can be virtually “wired” together. Selecting a filter will populate its options on the right hand side, with sliders and input boxes that allow you to play around with their parameters. When you want to see the final result, just click “Render Preview” and wait a bit.

If there was any downside, it seems like ~~whatever box the site is running on~~ the overhead of running in the browser doesn’t provide it a lot of horsepower. Even with the relatively low resolution of the demo videos available, the console output at the top of the page shows FFmpeg sometimes flirts with a processing speed measured in single-digit frames per second. Still, for a filter playground, it gets the job done. Perhaps the best part of the whole tool is that you can then copy your properly formatted command right out of the browser window and into your terminal so you can put it to work on your local files.

FFmpeg is one of those programs you should really be familiar with because it often proves useful in unexpected ways. The ability to manipulate audio and video with just a few keystrokes can really come in handy, and we’ve seen this open-source tool used for everything from compressing podcasts onto floppy disks to overlaying real-time environmental data onto a video stream.

DisplayPort: A Better Video Interface

July 11, 2023 by Arya Voronova 75 Comments

Over the years, we’ve seen a good number of interfaces used for computer monitors, TVs, LCD panels and other all-things-display purposes. We’ve lived through VGA and the large variety of analog interfaces that preceded it, then DVI, HDMI, and at some point, we’ve started getting devices with DisplayPort support. So you might think it’s more of the same. However, I’d like to tell you that you probably should pay more attention to DisplayPort – it’s an interface powerful in a way that we haven’t seen before.

The DisplayPort (shortened as DP) interface was explicitly designed to be a successor to VGA and DVI, originating from the VESA group – an organization created by multiple computer-display-related players in technology space, which has previously brought us a number of smaller-scale computer display standards like EDID, DDC and the well-known VESA mount. Nevertheless, despite the smaller scale of previous standards, DisplayPort has since become a hit in computer display space for a number of reasons, and is more ubiquitous than you might realize.

You could put it this way: DisplayPort has all the capabilities of interfaces like HDMI, but implemented in a better way, without legacy cruft, and with a number of features that take advantage of the DisplayPort’s sturdier architecture. As a result of this, DisplayPort isn’t just in external monitors, but also laptop internal displays, USB-C port display support, docking stations, and Thunderbolt of all flavors. If you own a display-capable docking station for your laptop, be it classic style multi-pin dock or USB-C, DisplayPort is highly likely to be involved, and even your smartphone might just support DisplayPort over USB-C these days. Continue reading “DisplayPort: A Better Video Interface” →

Enhance VR Immersion By Shoehorning An Ambilight Into A Headset

July 9, 2023 by Donald Papp 5 Comments

Everyone wants a wider field of view in their VR headsets, but that’s not an easy nut to crack. [Statonwest] shows there’s a way to get at least some of the immersion benefits with a bit of simple hardware thanks to the VR Ambilight.

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System Essentially Contradicting American Methods

July 5, 2023 by Jenny List 36 Comments

Today, acronyms such as PAL and initialisms such as NTSC are used as a lazy shorthand for 625 and 525-line video signals, but back in the days of analogue TV broadcasting they were much more than that, indeed much more than simply colour encoding schemes. They became political statements of technological prowess as nations vied with each other to demonstrate that they could provide their citizens with something essentially home-grown. In France, there was the daddy of all televisual symbols of national pride, as their SECAM system was like nothing else. [Matt’s TV Barn] took a deep dive into video standards to find out about it with an impressive rack of test pattern generation equipment.

At its simplest, a video signal consists of the black-and-while, or luminance, information to make a monochrome picture, along with a set of line and frame sync pulses. It becomes a composite video signal with the addition of a colour subcarrier at a frequency carefully selected to fall between harmonics of the line frequency and modulated in some form with the colour, or chrominance, information. In this instance, PAL is a natural progression from NTSC, having a colour subcarrier that’s amplitude modulated and with some nifty tricks using a delay line to cancel out colour shifting due to phase errors.

SECAM has the same line and frame frequency as PAL, but its colour subcarrier is frequency modulated instead of amplitude modulated. It completely avoids the NTSC and PAL phase errors by not being susceptible to them, at the cost of a more complex decoder in which the previous line’s colour information must be stored in a delay line to complete the decoding process. Any video processing equipment must also, by necessity, be more complex, something that provided the genesis of the SCART audiovisual connector standard as manufacturers opted for RGB interconnects instead. It’s even more unexpected at the transmission end, for unlike PAL or NTSC, the colour subcarrier is never absent, and to make things more French, it inverted the video modulation found in competing standards.

The video below takes us deep into the system and is well worth a watch. Meanwhile, if you fancy a further wallow in Gallic technology, peer inside a Minitel terminal.

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Teardown Of An Aircraft Video Symbol Generator

June 19, 2023 by Dave Rowntree 17 Comments

[Adrian Smith] recently scored an avionics module taken from a British Aerospace 146 airliner and ripped it open for our viewing pleasure. This particular aircraft was designed in the early 1980s when the electronics used to feed the various displays in the cockpit were very different from modern designs. This particular box is called a ‘symbol generator’ and is used to generate the various real-time video feeds that are sent to the cockpit display units. Various instruments, for example, the weather radar, feed into it, and it then reformats the video if needed, mixing in any required additional display.

Top view of the symbol generator instrument rack

There are many gold-plated chips on these boards, which indicates these may be radiation-hardened versions of familiar devices, most of which are 54xx series logic. 54xx series logic is essentially the same functionally as the corresponding 74xx series, except for the much wider operating temperature range mandated by military and, by extension, commercial aviation needs. The main CPU board appears to be based around the Intel 8086, with some Zilog Z180 compatible processors used on the two video display controller boards. We noted the Zilog Z0853604, which is their counter/timer/GPIO chip. Obviously, there are many custom ASICs produced by Honeywell as well as other special order items that you’ll never find the datasheet for. Now there’s a challenge!

Finally, we note the standard 400 Hz avionics-standard power supply, which, as some may know, is the standard operating frequency for the AC power system used within modern aircraft systems. The higher frequency (compared to 50 or 60 Hz) means the magnetic components can be physically smaller and, therefore, lighter for a given power handling capability.

We see a lot of avionics teardowns, likely because they’re fascinating. Here’s some more British military gear, an interesting RF distance measuring box from the 1970s, and finally, some brave soul building their own avionics gear. What could possibly go wrong?

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Motion Canvas Helps Get Your Point Across

June 5, 2023 by Matthew Carlson 1 Comment

Generating videos for projects can be difficult. Not only do you have to create the thing, but you film the process and cut it together in a story that a viewer can follow. Explaining complex topics to the viewer often involves a whiteboard of some sort, but as we all know, it’s not always a perfect solution. [Jacob] was working on a video game and making videos to document the progress and built a tool called Motion Canvas to help visualize topics like custom shaders. A few months ago, he decided to release it as an open source project.

Since then, it has seen quite a few forks and GitHub forks with a lively showcase on the community Discord. Looking at the docs, it is pretty easy to see why. The interface allows you to write procedural animations using the async semantics of TypeScript while still offering the GUI interface we expect from our video editors. In particular, the signal system allows dependencies to be defined between values. The system runs in Node, and the GUI runs in your browser locally while you edit the files in your terminal/notepad/IDE. CSS and Flexbox are available as the video is rendered to a web canvas and then compiled into a video via FFMPEG. The documentation is quite extensive, and it’s a great example of a tool someone built to fit a need they had going on to become something a little more fantastic.

This isn’t the first time we’ve discussed how to share your projects with the world, and we’ll freely admit we have a bit of bias toward encouraging folks to document their projects.

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Mangle Videos With RecurBOY And A Raspberry Pi Zero

May 28, 2023 by Elliot Williams 6 Comments

You used to need a lot of equipment to be a video DJ. Now you can do it all with a Raspberry Pi Zero and [cyberboy666]’s recurBOY. And if you missed out on the 1970’s video-editing psychedelia, now’s your chance to catch up – recurBOY is a modern video synth with all of the bells and whistles, and it’ll fit in your pocket. Check out [cyberboy666]’s demo video if you don’t yet know what you’re getting into. (Embedded below.)

RecurBOY has four modes: video, shader, effects, and external input, and each of these is significantly cooler than the previous. Video mode plays videos straight off of the SD card through the recurBOY’s composite video out. Shader mode lets you program your own shaders using the GLES shader dialect for resource-constrained devices. And this is where the various knobs and buttons come in. You can program the various shader routines to read any of the pots as input, allowing you to tweak the graphics demos on the fly.

Effects mode overlays your shaders on the video that’s playing, and external mode allows you to plug in a USB video capture card or a webcam so you can do all that same mangling with a live camera feed. And these two modes are where it gets awesome. The shader effects in the demo video cover all of the analog classics – including bloom and RGB separation – but also some distinctly digital effects. And again, you can tweak them all live with the knobs. Or plug in a MIDI controller and control it all externally. What hasn’t he thought of?

Old school analog video effects are really fun, and recurBOY brings them to you with the flexibility of modern shader coding. What’s not to love? If you want to see the pinnacle of the pre-digital era, that would be the Scanimate. For a video synth that integrates with your audio synth, check out Hypno. And if glitching the video is more your style, you can hijack the RAM of a VGA/composite converter.

Trippy, man!

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