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• FFMPEG Chapter Metadata added to a song file is sometimes off by 1 second

  6 février 2021, par Elthfa

  I attempted to add chapter metadata to a .opus file, but afterward, the file metadata showed timestamps different than the ones I attempted to add.
It seems to be adding an extra second to the timestamps under certain conditions.
I'm not sure if this is a bug, or if maybe I am just using the command wrong.

  


  Here are the commands I performed :

  


  First I removed all existing metadata from the file. I did this using a command I found on stack overflow :

  


  ffmpeg -i test_song.opus -c copy -map_metadata -1 -fflags +bitexact -flags:a +bitexact no_metadata.opus


  


  Then I added the new metadata from an external file I had written :

  


  ffmpeg -i no_metadata.opus -f ffmetadata -i metadata.txt -c copy -map_metadata 1 out.opus


  


  The file 'metadata.txt' looks like :

  


  ;FFMETADATA1
[CHAPTER]
TIMEBASE=1/1000
START=0
END=400
title=400 ms
[CHAPTER]
TIMEBASE=1/1000
START=400
END=500
title=100 ms
[CHAPTER]
TIMEBASE=1/1000
START=500
END=2000s
title=1500 ms
[CHAPTER]
TIMEBASE=1/1000
START=2000
END=97000
title=The Rest


  


  When I print out the basic data from the file, not all the timestamps shown match the ones I had in the metadata file.

  


  > ffmpeg -i out.opus
...
Input #0, ogg, from 'out.opus':
  Duration: 00:01:37.00, start: 0.000000, bitrate: 147 kb/s

    Chapter #0:0: start 0.000000, end 0.400000
    Metadata:
      title           : 400 ms

    Chapter #0:1: start 0.400000, end 1.500000
    Metadata:
      title           : 100 ms
    
    Chapter #0:2: start 1.500000, end 2.000000
    Metadata:
      title           : 1500 ms
    
    Chapter #0:3: start 2.000000, end 97.000000
    Metadata:
      title           : The Rest
...


  


  You can see the issues for chapters 0:1 and 0:2, which show a start and end time of 1.5 seconds respectively, when it should be 0.5 seconds for each.
I tried several combinations for this, and it seems that if the digit in the hundreds of milliseconds place is between 5 and 9 inclusive, it adds and extra second to the timestamp it saves in the metadata.

  


  Is this due to me using the command wrong ? Or formatting the metadata file wrong ? Or is there an issue in the code with rounding timestamps ?

  


  Thanks !

  


• Rtmp streaming not playing on VLC player

  7 février 2021, par Madhuraank B

  In terminal :

  


  ffmpeg -f v4l2 -i /dev/video0 -vcodec libx264 -preset ultrafast -pix_fmt yuv420p -s 1280x720 -r 30 -b:v 1500k -bufsize 1500k -maxrate 7000k -f flv rtmp://192.168.1.6:1935/live/test


  


  I get :

  


  


  Output #0, flv, to 'rtmp ://192.168.1.6:1935/live/test' :
Metadata :
encoder : Lavf58.20.100
Stream #0:0 : Video : h264 (libx264) ([7][0][0][0] / 0x0007), yuv420p, 1280x720, q=-1—1, 1500 kb/s, 30 fps, 1k tbn, 30 tbc
Metadata :
encoder : Lavc58.35.100 libx264
Side data :
cpb : bitrate max/min/avg : 7000000/0/1500000 buffer size : 1500000 vbv_delay : -1
frame= 115 fps=0.1 q=21.0 size= 3088kB time=00:00:17.96 bitrate=1407.9kbits/s speed=0.0141x

  


  


  When I open VLC player and open network stream in network rtmp://192.168.1.6/live/test, but it does not play it shows no error it just keeps on loading.

  


  Thanks in advance

  


• Conditional formats in Laravel FFMPEG

  29 décembre 2020, par JJ The Second

  I'm currently using Laravel FFMPEG in a Laravel project and running followings which works well https://github.com/protonemedia/laravel-ffmpeg

  


  Here is an example of code that is working :

  


   $lowBitrate = (new X264)->setKiloBitrate(250);
            $midBitrate = (new X264)->setKiloBitrate(500);
            $highBitrate = (new X264)->setKiloBitrate(1000);
            $superBitrate = (new X264)->setKiloBitrate(1500);

            FFMpeg::open('steve_howe.mp4')
                ->exportForHLS()
                ->addFormat($lowBitrate, function($media) {
                    $media->addFilter('scale=640:480');
                })

                 ->addFormat($midBitrate, function($media) {
                    $media->scale(960, 720);
                })
                ->addFormat($highBitrate, function ($media) {
                    $media->addFilter(function ($filters, $in, $out) {
                        $filters->custom($in, 'scale=1920:1200', $out); // $in, $parameters, $out
                    });
                })
                ->addFormat($superBitrate, function($media) {
                    $media->addLegacyFilter(function ($filters) {
                        $filters->resize(new \FFMpeg\Coordinate\Dimension(2560, 1920));
                    });
                })
                ->save('adaptive_steve.m3u8');


  


  Now, my challenge is that on client side, my users need to select what formats they'd like to include in transcoding job and one job may contain 2 bitrate variation or more so there is a need to have a conditional statement before calling ->addFromat()

  


  Ideally I'd need to approach this :

  


   $lowBitrate = (new X264)->setKiloBitrate(250);
        $midBitrate = (new X264)->setKiloBitrate(500);
        $highBitrate = (new X264)->setKiloBitrate(1000);
        $superBitrate = (new X264)->setKiloBitrate(1500);

        FFMpeg::open('steve_howe.mp4')
            ->exportForHLS()
            ->addFormat($lowBitrate, function($media) {
                $media->addFilter('scale=640:480');
            })
             /// adding if statement here
             ->addFormat($midBitrate, function($media) {
                $media->scale(960, 720);
            })
            ->addFormat($highBitrate, function ($media) {
                $media->addFilter(function ($filters, $in, $out) {
                    $filters->custom($in, 'scale=1920:1200', $out); // $in, $parameters, $out
                });
            })
            ->addFormat($superBitrate, function($media) {
                $media->addLegacyFilter(function ($filters) {
                    $filters->resize(new \FFMpeg\Coordinate\Dimension(2560, 1920));
                });
            })
            ->save('adaptive_steve.m3u8');


  


  No idea how to add a if/else statement here. How do you think I should approach this ?

  


  Thanks