• 44 Posts
  • 1.24K Comments
Joined 3 years ago
cake
Cake day: June 22nd, 2023

help-circle


  • There’s hardware that works under Linux, hardware that doesn’t work, and hardware that sort-of-works or is marginal. Lots of graphics cards are in the marginal or don’t-work category. I always try to avoid them. Maybe that’s not much help. If you’re on a desktop PC, your CPU is likely to have some graphics support of its own: can you bypass or pull out the graphics card? They are mostly for gaming. For normal desktop stuff you should be ok without it.




  • IDK if there are many of those things still being made, but sure, if there’s any private info on the player and you’re trying to be ultra careful, then get one without Bluetooth. I can also imagine (IDK if this has actually been done) someone using a bluetooth attack to turn the player into an audio bug from (say) the next room.

    Players do tend to have built in microphones so you can use them as audio recorders. I had (and mostly still have) a bunch of different ones, though they were audio only and not video, or at any rate had tiny screens. There are tons of them on ebay.

    If you’re going to carry a big player with video and an ebook reader, why not just take your phone? Put it in a mode that blocks all calls. Or get another phone and use it with no sim and turn off the wifi. Then you can run your usual audio and video players. Dedicated players were once popular but now are very niche, since everyone uses their phone now.

    FIIO makes some good ones if you still want to shop around.






  • You have it approximately right, serving from an https domain does nothing to authenticate the thing being downloaded. There is such a thing as signed downloads, authenticated by a “code signing certificate”, used for things like Windows installers. Linux distros tend to use PGP signatures instead. Signing the download can in principle be a more secure process than serving a domain over https, since servers get pwned all the time. The download signing, by contrast, can in principle be done completely offline. There is a catch to that involving connecting to a timestamp server, but that gets into the weeds.

    https://en.wikipedia.org/wiki/Code_signing



  • So find the places where the bitrate changes and decode and analyze those frames. Outdoors, true, leaves blow around, there is wildlife etc. A harder problem. I was thinking more of an indoor security camera. As for examining the bit rate, I guess it depends on the encoding, but e.g. in .mp4 there is a “key frame” every so often and then a bunch of delta frames, and if stuff is changing too fast iirc the key frames become more frequent. But I believe there is a fast way to scan for them, that is needed for fast forwarding in video.


  • I have to wonder if there’s a faster way than literally decoding the video and analyzing the decoded frames, if that’s how you’re doing it with ffmpeg. Video compression revolves around motion estimation so maybe it’s possible to just scan the file and find frames where the motion vectors (the data saying how the stuff in the picture is changing at a given frame) suddenly get larger. I assume this is for something like a security video that usually shows a static picture, and OP wants to flag when someone enters the room. In that case there will be almost no motion most of the time, and suddenly there will be some.