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• Overlay a video and an image over a background video and shift that background video's position to the right

  4 août 2023, par sybr

  I'm currently working on a way to improve my production process for the videos that I'm making. I usually edit videos using two folders full of clips. Being able to automate putting these together in Premiere would save me a lot of time.

  


  I'm using the FFMpegCORE C# library, as well as Xabe.FFMpeg to achieve what I'm trying to do, and I've currently reached the point of creating two separate videos using the clips I mentioned earlier.

  


  The final step that I need to solve is to overlay the overlay video (overlay.mp4) over the background video (background.mp4), add an overlay image to add a clean divider (overlay.png) between the edges of the videos, and to somehow shift the position of the background video 33% to the right (background.mp4).

  


  This is the script I've come up with so far :

  


  ffmpeg -i overlay.mp4 -i background.mp4 -i overlay.png -filter_complex \ 
"[1:v]scale=608:1080[a]; [0:v]pad=1920:1080[b]; [b][a]overlay[out]; \
[out][2:v]overlay[out]; [0][1]amix[a];" \
-map [out] -map [a] -c:v libx264 -crf 30 -pix_fmt yuv420p -y output.mp4


  


  Is there a way to shift the background video to the right ? Or should I manually edit the video files ?

  


  Would love some help here, also eager to learn more about FFmpeg, so some explanation would be highly appreciated !

  


  Edit :

  


  Just found the solution, padding the background video for 33% and then cropping the final out back to 1920x1080 seemed to do the trick !

  


  ffmpeg -i overlay.mp4 -i background.mp4 -i overlay.png -filter_complex "[1:v]scale=608:1080[a]; [0:v]pad=2560:0:x=1920:y=1080[b]; [b][a]overlay[out]; [out][2:v]overlay[out]; [out]crop=1920:1080:0:0[out]; [0][1]amix[a];" -map [out] -map [a] -c:v libx264 -crf 30 -pix_fmt yuv420p -y output.mp4


  


• FFmpeg/C/C++ : where is located and how decode Closed Caption(608) in Matrox DVCPRO SD files using ffmpeg and c/c++ ?

  2 mars 2020, par Helmuth Schmitz

  I’m a lit bit crazy with some especific video files. I want to decode them using ffmpeg/c++, specifically decode 608 Closed Captions. The AVI file format/codec is DVCPRO at SD(720x480) resolution. The enconder is "Matrox DSX AVI file . Format : 6. Build : 1.0.0.451" That’s was ok, until moment i tried to see or decode 608 closed captions. There was nothing at line 21. So, i decid to play this file in Matrox Sample Video Player(an example of their SDK) and for my surprise there was 608 closed captions. So, i read Matrox SDK documentation, and found this

  Using closed caption information
  
  Some of the Matrox NTSC codecs can extract the closed caption information from the
  
  video buffers and store it as metadata in the compressed buffer. On decompression,
  
  these same codecs can restore the lines to their proper position. Other NTSC codecs
  
  just encode the closed caption lines as video data. The closed caption lines that are
  
  extracted are defined by the EIA-608 specification. The two lines are defined as lines
  
  21 from both the first and second fields.
  
  The following codecs keep the closed caption lines as metadata (NTSC only):
  
  • Matrox DV (encode and decode).
  
  • Matrox MPEG-2 I-frame (encode and decode).
  
  • Matrox MPEG-2 IBP, except 720×512 resolution (decode only).
  
  The following codecs keep the closed caption lines as video data (NTSC only):
  
  • Matrox D10 (encode and decode).
  
  • Matrox MPEG-2 IBP in 720 ×512 resolution (decode only).
  
  • Matrox M-JPEG (decode only).

  So, i thought that VBI or Closed Caption(608) will be stored at some metadata. But, exploring the entire file using ffmpeg/libavcodec with C/C++, i found nothing "hide" in metadata. Even in frames metadata. Is like magic. There is nothing in line 21 and nothing in metadata’s. So, how Matrox sample example is the only one video player that show’s it ?

• C# - Discord.Net - Trying to read audio from soundcloud and transmit it to discord

  28 mars 2022, par Bruno Braga

  I am currently working on a discord bot that is able to play a song using soundcloud.
Unfortunately, I can't seem to figure out how to get it to read from the url and stream it !
The bot it made in C#, and uses Discord.net library and ffmpeg for the audio.
Would love to hear some suggestions !

  


  These are the three functions involved :

  


  [Command("teste", RunMode = RunMode.Async)]
public async Task Play(IVoiceChannel channel = null)
{
    var audioClient = await JoinChannel(channel);
    var url = "https://soundcloud.com/campatechlive/campatech-live-feat- 
        matheus-moussa-arabian-system-vol-2-psy-trance-150-original-mix";

    var ffmpeg = new Ffmpeg(audioClient);
    await ffmpeg.SendAsync(url);
}

public async Task SendAsync(string path)
{
    using (var ffmpeg = CreateStream(path))
    using (var output = ffmpeg.StandardOutput.BaseStream)
    using (var discord = _client.CreatePCMStream(AudioApplication.Mixed))
    {
        try { await output.CopyToAsync(discord); }
        finally { await discord.FlushAsync(); }
    }
}

private Process? CreateStream(string path)
{
    return Process.Start(new ProcessStartInfo
    {
        FileName = "ffmpeg",
        Arguments = $"-hide_banner -loglevel panic -i \"{path}\" -ac 2 -f 
        s16le -ar 48000 pipe:1",
        UseShellExecute = false,
        RedirectStandardOutput = true,
    });
}


  


  I'm guessing it's something on the ffmpeg arguments, but can't kind of figure out what.

  


  I've tried a bunch of different arguments on ffmpeg, but none of them worked.
Anyone can lend me a hand ?