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• Video converter library for Android [closed]

  17 décembre 2019, par Sushant

  I am trying to convert video formats by using FFmpeg. I’ve converted video from mp4 to mkv but it’s increasing the file size. Are there any good video trans-coding libraries that can be recommended ?

• mpeg12dec : move setting first_field to mpeg_field_start()

  17 décembre 2016, par Anton Khirnov

  mpeg12dec : move setting first_field to mpeg_field_start()
  For field picture, the first_field is set based on its previous value.
  
  Before this commit, first_field is set when reading the picture
  
  coding extension. However, in corrupted files there may be multiple
  
  picture coding extension headers, so the final value of first_field that
  
  is actually used during decoding can be wrong. That can lead to various
  
  undefined behaviour, like predicting from a non-existing field.
  Fix this problem, by setting first_field in mpeg_field_start(), which
  
  should be called exactly once per field.
  CC : libav-stable@libav.org
  
  Bug-ID : 999
  

  • [DBH] libavcodec/mpeg12dec.c

• Why does fluent-ffmpeg only work when it throws the error Output stream closed

  29 mars 2024, par volume one

  I am using fluent-ffmpeg to process a video file (and then upload that to Amazon S3). The code is very straightforward but it only works if :

  


  

  • pipe option {end: true} is set in .output()

  


  • which has a side-effect that causes the following console log output

  


  


  


  Processing : 19.261847354642416% done Processing :
32.365144874807335% done Processing : 48.80978326261429% done Processing : 78.35771917058617%
Processing : 91.49377493455148% done Processing :
99.91264359125745% done An error occurred : Output stream closed

  


  


  Despite that error, it seems the file is generated correctly and it gets uploaded to Amazon S3 fine.

  


  This is the fluent-ffmpeg code :

  


  import {PassThrough} from 'node:stream';
import FFMpeg from 'fluent-ffmpeg';

let PassThroughStream = new PassThrough();

             FFMpeg('/testvideo.mp4')
                    .videoCodec('libx264')
                    .audioCodec('libmp3lame')
                    .size(`640x480`)
                    // Stream output requires manually specifying output formats
                    .format('mp4')
                    .outputOptions('-movflags dash')
                    .on('progress', function (progress) {
                        console.log('Processing: ' + progress.percent + '% done');
                    })
                    .on('error', function (err) {
                        console.log('An error occurred: ' + err.message);
                    })
                    .on('end', function () {
                        console.log('FFMpeg Processing finished!');
                    })
                    .output(PassThroughStream, {end: true})
                    .run();

   // Now upload to S3
    try {
          await s3Upload({
              AWSS3Client: 'mys3client',
              Bucket: 'publicbucket,
              ACL: "public-read",
              ContentType: 'video/mp4',
              Key: 'whoever/whatever.mp4',
              Body: PassThroughStream
           });
    } catch (error) {
                    console.log(`s3Upload error`, error)
                }


  


  If I set the pipe output() option to {end: false} then there is no error from fluent-ffmpeg and I get "Processing: 100% done FFMpeg Processing finished!" as the final console log.

  


  BUT the problem is that the s3Upload() does not do anything. There are no errors. Just no activity.

  


  I feel very uncomfortable letting fluent-ffmpeg end in an error even if the code itself does the job intended. It will also cause testing to fail. What could be the issue ?

  


  The command line code is : ffmpeg -i https:/xxxbucket.s3.amazonaws.com/14555/file-example.mp4 -acodec libmp3lame -vcodec libx264 -filter:v scale=w=trunc(oh*a/2)*2:h=480 -f mp4 -movflags dash pipe:1