Recherche avancée

Sur d’autres sites (6203)

• Concatenate multiple video files alongside delayed audio files

  28 mars 2022, par Spartan 117

  I am currently working on a utility that is responsible for pulling audio and video files from the cloud and merging them together via FFMPEG. As I am new to FFMPEG, I am going to split the question into an FFMPEG part and a C# part just so people can answer either 1 part or the other (or both !).

  


  FFMPEG Part

  


  Currently, I have a working FFMPEG arg if there is only 1 video file present and it needs to be merged with multiple files.

  


  ffmpeg -i input1.mkv -i input1.mka -i input2.mka -i input3.mka -i input4.mka -filter_complex "[1:a]adelay=0s:all=1[a1pad];[2:a]adelay=20s:all=1[a2pad];[3:a]adelay=30s:all=1[a3pad];[4:a]adelay=40s:all=1[a4pad];[a1pad][a2pad][a3pad][a4pad]amix=inputs=4:weights=1|1|1|1[aout]" -map [aout] -map 0:0 output4.mkv


  


  The delays you see in there are determined by subtracting the start time of each file from the start time of the earliest created audio or video file. I know that if I wanted to create a horizontal stack of multiple videos, i could just do

  


  ffmpeg -i input1.mkv -i input1.mka -i input2.mkv -i input2.mka -i input3.mka -i input4.mka
-filter_complex 
"[2:v]tpad=start_duration=120:color=black[vpad]; 
 [3:a]adelay=120000:all=1[a2pad]; 
 [4:a]adelay=180000:all=1[a3pad];
 [5:a]adelay=200000:all=1[a4pad]; 
 [0:v][vpad]hstack=inputs=2[vout]; 
 [1:a][a2pad][a3pad][a4pad]amix=inputs=4:weights=1|1|1|1[aout]" 
 -map [vout] -map [aout] 
 output.mkv


  


  but what I want to do is both keep those delays for the audio and video files AND concatenate (not stack) those videos, how would i go about doing that ?

  


  C# Part

  


  You see that giant arg up there ? The utility is supposed to generate that based on a List of recordings. Here is the model.

  


  List<filemodel> _records;&#xA;public class FileModel {&#xA;  public string Id { get; set; }&#xA;  public string FileType { get; set; }&#xA;  public string StartTime { get; set; }&#xA;}&#xA;</filemodel>

  


  The utility has to then go through that list and create the arg (as seen in the FFMPEG part) to be executed by the Xabe.FFMPEG package. The way i was thinking to approach this is to basically create 2 string builders. 1 string builder will be responsible for dealing with the inputs, the other string builder. Here is what i have so far

  


  private async Task CombineAsync()
    {
        var minTime = _records.Min(y => Convert.ToDateTime(y.StartTime));
        var frontBuilder = new StringBuilder("-y ");
        var middleBuilder = new StringBuilder("-filter_complex \"");
        var endString = $" -map [vout] -map [aout] {_folderPath}\\CombinedOutput.mkv";

        for (var i = 0; i < _records.Count; i++)
        {
            var type = _records[i].FileType.ToLower();
            var delay = (Convert.ToDateTime(_records[i].StartTime).Subtract(minTime)).TotalSeconds;
            frontBuilder.Append($"-i {_folderPath + "\\" + _records[i].Id} ");
            var addColon = i != _records.Count - 1 ? ";" : "";
            middleBuilder.Append(type.Equals("video") ? $"[{i}:v]tpad=start_duration={delay}:color=black[v{i}pad]{addColon} " : $"[{i}:a]adelay={delay}s:all=1[a{i}pad]{addColon} ");
        }
        middleBuilder.Append("\"");
        Console.WriteLine(frontBuilder.ToString() + middleBuilder.ToString() + endString);
        // var args = frontBuilder + middleBuilder + endString;
        // try
        // {
        //     var conversionResult = await FFmpeg.Conversions.New().Start(args);
        //     Console.WriteLine(JsonConvert.SerializeObject(conversionResult));
        // }
        // catch (Exception e)
        // {
        //     Console.WriteLine(e);
        // }
    }


  


  


  1. Is this the correct way to go about building the argument out ?

     


  


  2. How in god's name do i get something like this in there, since it relies on naming and total count for the piping and inputs=

     


       [0:v][vpad]hstack=inputs=2[vout]; // This part will change for video concatenation depending on what gets answered above
  [1:a][a2pad][a3pad][a4pad]amix=inputs=4:weights=1|1|1|1[aout]


     


  


  


• FFmpeg ubuntu auto transcoding script [on hold]

  11 décembre 2015, par Sambir

  Hi guys i want to create an ffmpeg script which picks up files from one folder transcodes them then deletes the source.

  So think of the following scenario :

  I place file A.mp4 and A.srt in folder input
  I also place file B.mp4 and B.srt in folder input

  In the night a script is executed which picks up these files places them in the folder "transcoding" then starts to transcode the movies one by one. So not parallel.

  When finished new files should be created in the output folder by the ffmpeg script. And the files in the folder "transcoding" should be deleted.

  Can anyone help me out here. It does not seem to be that complex but since I am not that good at coding any help is appreciated :)

• Add metadata to flv files with ffmpeg instead of flvmdi

  30 juillet 2012, par user1476852

  I have made a player for stream flv movies in flash with netstream but it needs some metadata information named " keyframe " containing two array of times and positions , some flv videos have this meta data and some not , i could add the keyframe metadata with a program named "flvmdi" and player worked properly , but i can`t install this software on my server for some reasons.
  I know that we can add metadata to a movie with ffmpeg function in PHP .
  Can i use ffmpeg function in PHP to add keyframe arrays as metadata to flv file ?
  How can we make times and positions arrays to inject to a flv file with ffmpeg in php ?