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• Use FFmpeg for continuous streaming from other source

  28 septembre 2017, par widgg

  We have an app that pipes its output, and its output is compress H264 data. The source of the data is from a 3d engine running in same app.

  We can easily pipe the output in FFmpeg to save as mp4 or even m3u8.

  It’s also possible to turn FFmpeg as a server to feed video files.

  So our objective is to have FFmpeg read that data, convert into into mp4 or m3u8 internally and then stream so that it can be read in the web browser.

  We don’t care about be able to replay some file, go back in time or whatever, we just care about the current value.

  Is there a way to do that ? Or a similar solution that would allow some close to that.

  Thanks

  I guess, if it’s possible, it’s like wanting to stream your personal webcam into the web browser. Then you could connect to that and see what is happening at home or wherever your webcam is.

• Compress video like whatsapp

  10 juillet 2021, par user1079425

  I'm not an expert in Video Editing but what I want to understand the logic of Whatsapp video processing.

  



  First of all I have noticed that whatever the file is, Whatsapp sets the limit of Uploaded videos to 16MB, after which whatsapp crops the video to not exceed the limit. is this a convention or it's a personal choice ?

  



  Secondly, When a video is recorded using the Camera it's not compressed by default, so whatsapp compresses it using FFMPEG I guess, and it takes no time. (tried for a video of 1min 1920x1080 with 125MB of size, becomes 640x360 with 5MB of size in no time, and the upload starts automatically).. how may they do this ? and why the choice of 640x360, It seems to me very fast for 2 asynchronous tasks : Compression + Upload.

  



  When I run the compression command ffmpeg -y -i in.mp4 -codec:v libx264 -crf 23 -preset medium -codec:a libfdk_aac -vbr 4 -vf scale=-1:640,format=yuv420p out.mp4 it takes approximatively 1 min and the video is being rotated !! :D

  



  Finally, when we download a video from Youtube it's already compressed (I guess) and whatsapp doesn't even try to compress it. So I think that it automatically detects thats the video is compressed. How can we detect this ?

  



  Thank you.

  


• What is the most suitable H265 setting converting from H264 on ffmpeg ?

  9 juin 2017, par minion007

  Currently, I was trying to convert my videos no matter personal videos or movies from H264 to H265. But that was much harder than what I expected.

  Firstly, it took me over 10 hours to build ffmpeg on Linux and I believe I’m still having some problems on dealing with this.

  Secondly, I notice there is degradation after converting by using the setting or parameters from Internet or ffmpeg official website. On the other hand, the video size would be the same or even bigger than the original video size if I use small crf like 23 or 28.

  For instance, sudo ffmpeg -i input.mp4 -c:v hevc -x265-params lossless -preset medium -crf 30 -c:a copy output.mkv

  sudo ffmpeg -i input.mp4 -c:v libx265 -x265-params lossless -preset medium -crf 30 -c:a copy output.mkv

  the above two settings give me the very small video size (between 21% 23% of the original video) which is the main reason why I want to convert my videos to H265 but drawback would be the quality of converted video is worse than the original video (I would may be between 30% 35% degradation).

  Thirdly, the size of video would be much bigger than the original size of video if I use the lossless parameter.

  sudo ffmpeg -i input.mp4 -c:v libx265 -x265-params lossless=1 -preset medium -crf 30 -c:a copy output.mkv

  the above setting can keep the quality of the original video but size would be huge (above 200% of original video).

  Is there any suggestion ?