Category Archives: Video

FFMPEG overlay needs “repeatlast” argument…

I use ffmpeg to add some information overlays to the videos that I often upload to YouTube. I’ve documented these before, but I had a problem that arose from time to time that I never figured out: occasionally my encodes would seemingly just go on forever, and never terminate. I discovered today that this was because the use of the “overlay” filter. It apparently keeps generating frames even after the main stream has terminated, which seems odd to me, but… whatever. If you add the repeatlast argument, you’ll get what you want.

Stashed here for reference later.

#!/bin/sh
ffmpeg -y -f concat -i files.txt -movflags +faststart -aspect 16:9 -crf 24 \
	-vf "scale=854:480, fade=in:0:30, hqdn3d [xxx] ; \
	     color=0x33669955:854x64 [yyy] ; \
	     [xxx] [yyy] overlay=0:416:repeatlast=0, \
	     drawtext=textfile=hdr:fontfile=/usr/share/fonts/truetype/ttf-dejavu/DejaVuSans-Bold.ttf:x=10:y=432:fontsize=16:fontcolor=white" \
	quad.mp4

Bit banger

Anyone who has seen my projects on the Atari 2600 might reasonably conclude that I have a thing for retro computing. The saying goes “it is no virtue to do with more, what can be done with less” and I can’t think of someone whose projects have embodied that more than demo coder Linus Akesson (lft). His latest demo runs on the tiniest of tiny Atmel processors, the ATTINY15. It has just 32 bytes of memory (just the registers, really) and room for 512 instructions. Yet, lft made a cool demo that runs on it, generating both video and sound. Oh, and he’s only running it at 1.6 Mhz (yes, 1.6 Megahertz). Very cool!


More details about Bit banger, and how he did it..

The Broadcaster Project, revisited

One year ago today, I first published a link to The Broadcaster Project, a site which had several tips on using command line tools such as ffmpeg to assemble videos. I use a similar technique to do my more recent videos: I take the raw footage from the camera and resize it, denoise it, and add some overlaid text before uploading it to YouTube. Revisiting The Broadcaster Project, I see they have a few more recipes that can be useful, such as ones for assembling time lapse movies and the like. I also found a reference to youtube-upload, a command line python script that can automatically upload videos from the command line, a part of my process that I still did with the web interface.

Watermarking and titling with ffmpeg and other open source tools…

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