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• How to save changes in video file in Ffmpeg C++ ?

  16 avril 2021, par TheSofya

  How to save changes in video file in Ffmpeg C++ ? Do we need encoder ? How to use avcodec_encode_video2 functions ?

  


  while (av_read_frame(pFormatCtx, &packet) >= 0)
    {

        if (packet.stream_index == videoStream) {
            avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet); 
            if (frameFinished) {
                sws_scale(sws_ctx, (uint8_t const* const*)pFrame->data,
                    pFrame->linesize, 0, pCodecCtx->height,
                    pFrameRGB->data, pFrameRGB->linesize);

                if (i == secretframe) {
                    //Here we change pixels
                    hidetext(pFrameRGB, pCodecCtx->width, pCodecCtx->height, secretframe);
                    //unhidetext(pFrameRGB, pCodecCtx->width, pCodecCtx->height, secretframe); 

                    std::cout << "\n\n" << i << "\n\n";
                }
                if (i > secretframe) { 
                break; 
                }
                i++;
            }
        }


  


• I am trying to use ffmpeg to separate audio from video, but after downloading the ffmpeg build I cannot seem to activate it in Power Shell [duplicate]

  19 janvier 2021, par Row Boater

  Ok, look y'all, I am NOT an aspiring programmer. I'm simply trying to separate audio from video of a youtube video I downloaded.

  


  What I've done :

  


  Downloaded YT vid using 4k video Downloader

  


  I downloaded ffmpeg build from https://ffmpeg.org/download.html#build-windows

  


  I downloaded WinZip in order to access the ffmpeg files.

  


  I thought I used winzip correctly, but whenever I paste the command code line recommended to me, ffmpeg -i video.mp4 -c:a pcm_s16le audio.wav, I receive the following :

  


  


  PS C :\Users\user\Videos\4K Video Downloader> ffmpeg -i video.mp4 -c:a
pcm_s16le audio.wav ffmpeg : The term 'ffmpeg' is not recognized as
the name of a cmdlet, function, script file, or operable program.
Check the spelling of the name, or if a path was included, verify that
the path is correct and try again. At line:1 char:1

  


  

  • ffmpeg -i video.mp4 -c:a pcm_s16le audio.wav

  


  • 


      + CategoryInfo          : ObjectNotFound: (ffmpeg:String) [], CommandNotFoundException
  + FullyQualifiedErrorId : CommandNotFoundException



    


  


  


  PS C :\Users\user\Videos\4K Video Downloader>

  


  


  This is all Phoenician to me, but what I take away is that I have not completed some step to fully incorporate the ffmpeg code into my system. I believe that I am not using Winzip correctly.

  


  Thanks for your time.

  


• FFMPEG recombine a video with its original uncropped version

  9 décembre 2022, par Skyler

  I have a video which I cropped to run through a script to process these files much quicker. I would like to now combine the cropped videos back in with their original uncropped version, using the audio from one of the files (the cropped one in this case). The script to crop was :

  


  ffmpeg -i file.mp4 -filter:v "crop=1000:1000:580:0" -crf 20 -preset slow smaller.mp4


  


  So how do I remerge them ?