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• How to use FFmpeg & "tee" to UDP video (only) stream to another computer while recording to computer with USB camera

  13 juillet 2020, par pomptondrive

  I'm trying to get "tee muxer" to work with FFmpeg, but I'm not having much luck. Basically I would like to stream a USB camera with UDP to another computer with an decent/acceptable result to monitor, while recording around 15 FPS in an economical (compressed) fashion that won't take up too much disk space. Honestly, I don't understand the entire syntax of using "tee"—I guess that's obvious. I have looked at some of the FFmpeg documentation, but it doesn't seem comprehensive enough in this instance.

  


  So, currently, I have experimented a little and this works for streaming (picking up with VLC on the other computer) :

  


  ffmpeg -f v4l2 -i /dev/video0 -profile:v high -pix_fmt yuvj420p -level:v 4.1 -preset ultrafast -tune zerolatency -vcodec libx264 -r 15 -b:v 512k -s 640x480 -f mpegts -flush_packets 0 udp://192.168.0.19:5000?pkt_size=1316


  


  I've also checked and this records OK (I do NOT actually want it to ffplay on this machine ; this was just some code I found to test.) :

  


  ffmpeg -f v4l2 -i /dev/video0 -map 0 -c:v libx264 -f tee "Documents/video01.mkv|[f=nut]pipe:" | ffplay pipe:


  


  So the next objective is to combine the two with tee, and do a UDP stream to the other computer, while recording an mkv file to the computer with the camera. I've tried several ways to do this with no success ; results have been just one or the other, because my syntax is crap, or I'm just particularly inept at this particular task. ;-)

  


  After that (icing on the cake) would be to create separate *.mkv files at 15-minute intervals, and have them self-destruct after a couple of days.

  


  Any help with the tee business would be greatly appreciated.

  


• fastest ways of cropping a fixed size image into 9 fixed size crops

  18 septembre 2022, par bit_scientist

  I have thousands of images in a folder and I need to crop each image(3840x2160) into 9 crops (1280x720) with the fastest way possible. The cropped images should preserve all the details of the original image as it may contain small objects of interest. I found that image_slicer does the job, but not sure about its speed.

  


  from image_slicer import slice
slice('cake.png', 9)


  


  I also looked at PIL (image_slicer uses it), Imagemagick and some other similar libraries, but was not able to evaluate their speed. Maybe ffmpeg has some line command to achieve my goal.

  


  Eventually, I need a Windows executable file where a user inserts a full path to images and gets cropped images for each image in the new folder.

  


• Create animated Gif in Kotlin

  27 octobre 2022, par Gregor Sotošek

  I am struggling with something I thought would be a piece of cake. In my Android App (jetpack compose variant), I want to save some screenshots (not many, 10-20 of them), and then "packed them" into animated GIF file, and then user would be able to share this GIF to other users. I am having a hard time "creating" or "saving" GIF file from saved screenshots. The only thing I found on web was pretty old post here

  


  1 : How to create an animated GIF from JPEGs in Android (development) but I just can't get it to work. All the others posts are related to "displaying" GIF in android, which is not my problem currently. If someone can point me in the right direction, would be very nice.

  


  I also try to make it to work with FFmpeg, but don't know how to either.
https://proandroiddev.com/a-story-about-ffmpeg-in-android-part-i-compilation-898e4a249422

  


  Thank you