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• Flutter app crashes in release mode when initializing FlutterFFmpegConfig() ;

  18 février 2021, par Mahmoud Eidarous

  The app is working on Android on Debug mode(only) with no errors in the logcat/terminal.
But when I tested it on iOS (even in debug mode), it crashes on a specific page.
After long tests, I could know that this line was causing the app to crash.

  


  FlutterFFmpegConfig _flutterFFmpegConfig = FlutterFFmpegConfig();


  


  If I comment that line, the app won't crash, but I need that line to manipulate videos in the app.

  


  I'm using flutter_ffmpeg: ^0.3.0 in pubspec.yaml, and full-gpl package is set in android\build.gradle

  


  ext {
    flutterFFmpegPackage  = "full-gpl"
}


  


  Related package initializations code snippet :

  


  final FlutterFFmpegConfig _flutterFFmpegConfig = new FlutterFFmpegConfig();
final FlutterFFmpeg _flutterFFmpeg = new FlutterFFmpeg();
final FlutterFFprobe _flutterFFprobe = new FlutterFFprobe();


  


  I'm not sure, but it seems like the app can't handle creating all these objects at the same class !
Anyone familiar with this problem ?

  


• How to save ffmpeg segmets to disk immediately with sub-second intervals ?

  20 octobre 2023, par amfast

  I'm trying to record video on a raspberry and have it save as much as possible (sub-second resolution) in case of a power cutoff.

  


  I use -f segment to save the encoded stream in 100ms segments with the hope that all but the interrupted (by power cutoff) segment will be saved in memory. Unfortunately, when cutting off power, all the destination files (output_0001.mp4, output_0002.mp4, ...) are created, but empty.

  


  To save the files to disk immediately, I added the -strftime 1 option that allows formatting the output filename as time. It seems weird that this is the (only ?) way to trigger immediate saving of files, but it works - untill I try to have segments smaller than 1 second. The problem seems to be that the format string %d, that previously added a sequence number in my output filenames, now represents "day" (i.e. date) and the smallest resolution time format string is %S for second. I saw %f suggested somewhere for smaller resolutions, but it only prints "%f".

  


  The result is that the segmentation part of ffmpeg does create 100ms segments and save them to disk immediately, but the strftime feature gives the output files names that only change every second, so all the interim files are overwritten.

  


  Example of the failing command below. Without the -strftime option this creates nice segments, but does not save them to disk immediately.

  


  libcamera-vid --flush \
    --framerate ${FRAMERATE} \
    --width ${WIDTH} \
    --height ${HEIGHT} \
    -n \
    -t ${TIMEOUT} \
    --codec yuv420 \
    -o - | 
ffmpeg \
    -fflags nobuffer \
    -strict experimental \
    -loglevel debug \
    -flags low_delay \
    -f rawvideo \
    -pix_fmt yuv420p \
    -s:v ${WIDTH}x${HEIGHT} \
    -r ${FRAMERATE} \
    -i - \
    -c:v h264_v4l2m2m \
    -f segment \
    -segment_time 0.1 \
    -segment_format mp4 \
    -reset_timestamps 1 \
    -strftime 1 \
    -b:v ${ENCODING_BITRATE} \
    -g 1 \
    "output_%04d.mp4"


  


  Question :
  
Is there another way besides -strftime to trigger immediate saving ? Or is there a mechanism to feed finer resolution format strings to the output filename ?

  


• Node package 'videoshow' ffmpeg error

  14 octobre 2015, par Jon Stevens

  I am using the npm library ’videoshow’ to build a video slideshow with images and audio. I have copied everything directly from the github wiki as far as installing the package and configuring ffmpeg to include the necessary flags. My code for the main ’generation.js’ node file :

  var videoshow = require('videoshow');
  
  
  
  var images = [
  
    '2.jpg',
  
    '4.jpg'
  
  ]
  
  
  
  var videoOptions = {
  
    fps: 25,
  
    loop: 5, // seconds
  
    transition: true,
  
    transitionDuration: 1, // seconds
  
    videoBitrate: 1024,
  
    videoCodec: 'libx264',
  
    size: '640x?',
  
    audioBitrate: '128k',
  
    audioChannels: 2,
  
    format: 'mp4'
  
  }
  
  
  
  videoshow(images, videoOptions)
  
    .audio('song.mp3')
  
    .save('video.mp4')
  
    .on('start', function (command) {
  
      console.log('ffmpeg process started:', command)
  
    })
  
    .on('error', function (err, stdout, stderr) {
  
      console.error('Error:', err)
  
      console.error('ffmpeg stderr:', stderr)
  
    })
  
    .on('end', function (output) {
  
      console.error('Video created in:', output)
  
    })

  Just running the above code with ’node generation.js’ which is the default usage and the exact settings they explain in the wiki is giving the error :

  ffmpeg process started : ffmpeg -i /tmp/videoshow-3fe871bc-e082-4ed8-bf47-f10c854f1718 -i /tmp/videoshow-a1595d76-dcbd-48c3-a8b3-cffac6951ed3 -y -filter_complex concat=n=2:v=1:a=0 video.mp4
  ffmpeg process started : ffmpeg -i /tmp/videoshow-7b78fd53-408f-40a8-8974-665f18f1fe41 -i song.mp3 -y -b:a 128k -ac 2 -r 25 -b:v 1024k -vcodec libx264 -filter:v scale=w=640:h=trunc(ow/a/2)*2 -f mp4 -map 0:0 -map 1:0 -t 10 -af afade=t=in:ss=0:st=0:d=3 -af afade=t=out:st=7:d=3 video.mp4
  Error : [Error : ffmpeg exited with code 1 : ]
  ffmpeg stderr : undefined

  If anyone has any experience at all with this library, any help is greatly appreciated !