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• Make mobile navigation work without JavaScript.

  20 février 2020, par blueimp

  Make mobile navigation work without JavaScript.

• How does Rust work with process arguments ?

  1er octobre 2022, par SoptikHa

  I'm really confused about Rust processes. I'm trying to call something like this :

  



  ffmpeg -i path/to/test-video.webm -ab 160k -ac 2 -vn -f mp3 -


  



  This should extract sound out of video and send it to stdout. So I've done this :

  



  let sound: std::process::Output = Command::new("ffmpeg")
    .arg(format!("-i {}", args.input.to_str().unwrap()))
    .arg("-ab 160k")
    .arg("-ac 2")
    .arg("-vn")
    .arg("-f mp3")
    .arg("-")
    .stdout(Stdio::piped())
    .stdin(Stdio::inherit())
    .stderr(Stdio::inherit())
    .output()
    .unwrap();


  



  But for some reason, this doesn't work. It prints this to stderr :

  



  Unrecognized option 'i path/to/test-video.webm'.
Error splitting the argument list: Option not found


  



  When I remove the slashes from args (so it looks like .arg(format!("i {}", ...)).arg("ab 160k")..., I get this :

  



  Output file #0 does not contain any stream


  



  I think I misunderstood how this works, but I tested it on other applications and it seemed to work the way I'm doing it now. What did I miss, how does Rust work with these arguments ?

  



  And just to be clear, I know about the ffmpeg crates, but they don't work for me for some reason, I can't even compile them.

  


• ffmpeg options that work with Chrome

  21 avril 2015, par James

  I am trying to find the magic options that make mp4 work in Chrome. I think my videos were working, but don’t seem to any more after Chrome updated.

  Chrome, Version 41.0.2272.101 (Windows)

  I tried some other machines and found some of the videos worked on older versions, and my Mac seems to still work on the latest Chrome.

  I am using the ffmpeg options to convert from png series,

  ffmpeg -framerate 10 -i dance%02d.png  -r 10 -pix_fmt yuv420p dance.mp4

  Some videos work, some don’t, some work some of the time, or stop half way through.

  I tried various other options like,

  ffmpeg -start_number 16 -framerate 10 -i dance%02d.png -r 10 -an -s hd720 \
  
  -vcodec libx264 -pix_fmt yuv420p -preset slow -profile:v baseline \
  
  -movflags faststart -y dance.mp4

  but this just seemed to make things worse.

  here is one of the videos,
  http://www.botlibre.com/media/a786625.mp4

  and another one,
  http://www.botlibre.com/media/a812450.mp4

  Firefox seems to work no problem, on any version, grey background though.
  IE works fine, white background.
  Safari works, grey background.

  Another thing, they videos used to have white background on older Chrome version, but now are grey, except on Mac still white.

  and one more thing. Webm format works, but anyone know the option to remove transparency ? I’m using,

  ffmpeg -i dance%02d.png  -r 10 -c:v libvpx -crf 10 -b:v 512k -c:a libvorbis dance.webm

  just want a solid white background.