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• How to add arbitrary or custom metadata in MP4 ?

  13 avril 2021, par 大大大大萝卜凉

  The MP4 muxer in ffmpeg only allows certain metadata by default. I would like to add :

  


  com.android.model: Mi 10 Pro
xyz: +22.9835+113.3621/
com.android.version: 1
com.android.manufacturer: Xiaomi


  


  How can I add this with ffmpeg ?

  


• Transcoding with custom commands using streamio-ffmpeg

  14 avril 2017, par ACIDSTEALTH

  I’m trying to transcode a video file using streamio-ffmpeg with some custom commands, but nothing I try seems to work. I want to transcode the video with the following options :

  ffmpeg -i input.mp4 -vf
  
      "format=yuv444p,
  
       drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max,
  
       drawtext=font='OpenSans-Regular,Sans':text='CUSTOM TEXT':fontcolor=0xFFFFFF:fontsize=24:x=(w-tw)/2:y=(h/PHI)+th,
  
       format=yuv420p"
  
  -c:v libx264 -c:a copy -movflags +faststart output.mp4

  I’ve tried the following code combinations without success :

  1. Tried removing the line breaks and converting the command string to an array, following the instructions in the docs.

     video = FFMPEG::Movie.new('input.mp4')
     
     opts = %w(ffmpeg -i input.mp4 -vf "format=yuv444p, drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max, drawtext=font='OpenSans-Regular,Sans':text='CUSTOM TEXT':fontcolor=0xFFFFFF:fontsize=24:x=(w-tw)/2:y=(h/PHI)+th, format=yuv420p" -c:v libx264 -c:a copy -movflags +faststart output.mp4)
     
     video.transcode('output.mp4', opts)

     But this yields the error :

     [NULL @ 0x7f962100e200] Unable to find a suitable output format for 'ffmpeg'
     
     ffmpeg: Invalid argument
     
     from /Users/ACIDSTEALTH/.gem/ruby/2.3.0/gems/streamio-ffmpeg-3.0.2/lib/ffmpeg/transcoder.rb:112:in `validate_output_file'

  2. Tried stripping out the input file name and output file name since the gem seems to handle that for you.

     video = FFMPEG::Movie.new('input.mp4')
     
     opts = %w(-vf "format=yuv444p, drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max, drawtext=font='OpenSans-Regular,Sans':text='CUSTOM TEXT':fontcolor=0xFFFFFF:fontsize=24:x=(w-tw)/2:y=(h/PHI)+th, format=yuv420p")
     
     video.transcode('output.mp4', opts)

     Which returns this error :

     [NULL @ 0x7fd0a9008c00] Unable to find a suitable output format for 'drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max,'
     
     drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max,: Invalid argument
     
     from /Users/ACIDSTEALTH/.gem/ruby/2.3.0/gems/streamio-ffmpeg-3.0.2/lib/ffmpeg/transcoder.rb:112:in `validate_output_file'

  3. Tried removing the -vf flag and just running everything within the quotation marks.

     video = FFMPEG::Movie.new('input.mp4')
     
     opts = %w(format=yuv444p, drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max, drawtext=font='OpenSans-Regular,Sans':text='CUSTOM TEXT':fontcolor=0xFFFFFF:fontsize=24:x=(w-tw)/2:y=(h/PHI)+th, format=yuv420p)
     
     video.transcode('output.mp4', opts)

     This returns another error :

     [NULL @ 0x7fab8101fe00] Unable to find a suitable output format for 'format=yuv444p,'
     
     format=yuv444p,: Invalid argument
     
     from /Users/ACIDSTEALTH/.gem/ruby/2.3.0/gems/streamio-ffmpeg-3.0.2/lib/ffmpeg/transcoder.rb:112:in `validate_output_file'

  4. Tried removing the format arguments since ffmpeg is clearly complaining about those.

     video = FFMPEG::Movie.new('input.mp4')
     
     opts = %w("drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max, drawtext=font='OpenSans-Regular,Sans':text='CUSTOM TEXT':fontcolor=0xFFFFFF:fontsize=24:x=(w-tw)/2:y=(h/PHI)+th")
     
     video.transcode('output.mp4', opts)

     Again another error :

     [NULL @ 0x7fc7f880a800] Unable to find a suitable output format for 'drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max,'
     
     drawbox=y=ih/PHI:color=0x000000@0.4:width=iw:height=48:t=max,: Invalid argument
     
     from /Users/ACIDSTEALTH/.gem/ruby/2.3.0/gems/streamio-ffmpeg-3.0.2/lib/ffmpeg/transcoder.rb:112:in `validate_output_file'

  5. Tried building a hash from the command string and feeding that into the transcode method.

     video = FFMPEG::Movie.new('input.mp4')
     
     opts = {
     
         '-vf' => {
     
             format: 'yuv444p',
     
             drawbox: {
     
                 y: 'ih/PHI', color: '0x000000@0.4', width: 'iw', height: '48', t: 'max'
     
             },
     
             drawtext: {
     
                 font: 'OpenSans-Regular,Sans', text: snap.title, fontcolor: '0xFFFFFF', fontsize: '24', x: '(w-tw)/2', y: '(h/PHI)+th'
     
             },
     
             format: 'yuv420p'
     
         }
     
     }
     
     video.transcode('output.mp4', opts)

     I also tried a variation without the -vf flag :

     video = FFMPEG::Movie.new('input.mp4')
     
     opts = {
     
         format: 'yuv444p',
     
         drawbox: {
     
             y: 'ih/PHI', color: '0x000000@0.4', width: 'iw', height: '48', t: 'max'
     
         },
     
         drawtext: {
     
             font: 'OpenSans-Regular,Sans', text: snap.title, fontcolor: '0xFFFFFF', fontsize: '24', x: '(w-tw)/2', y: '(h/PHI)+th'
     
         },
     
         format: 'yuv420p'
     
     }
     
     video.transcode('output.mp4', opts)

  These both produced an output.mp4 video file but the output file was unchanged from the input. There was no text overlay.

  Nothing I try seems to work. What am I doing wrong here ?

• How to change resolution without compromising video quality using ffmpeg ?

  20 mars 2024, par blake banker

  I'm trying to develop a simple video transcoding system.
When you upload a video,
After extracting the video and audio separately,
I want to encode them at 360, 720, and 1080p resolutions respectively and then merge them to create three final mp4 files.
At this time, I have two questions.

  


  


  1. Is there a big difference between encoding the video and audio separately in the original video file and encoding the original video file as is ? In a related book, it is said that a system is created by separating video and audio, and I am curious as to why.

     


  


  2. I want to change the resolution without compromising the original image quality. At this time, the resolution of the uploaded file can be known at the time of upload. As a test, I created files according to each resolution, and found that the image quality was damaged. If I want to change only the resolution while keeping the original image quality, I would like to know how to adjust each ffmpeg option. We plan to change it to 360, 720, and 1080p.