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• ffmpeg include issue - some functions are missing

  27 septembre 2019, par Thomas Ayoub

  I try to follow and adapt this example to convert a video thanks to FFMPEG but some function seems to be missing like :

  int avcodec_open ( AVCodecContext * avctx, AVCodec * codec)     

  When I go in the doc to see where it come from, I find it in the file libavcodec/avcodec.h which is included in my program #include "libavcodec/avcodec.h" (in the top of my .h file).

  Given this, I don’t understand why Qt throw me this error :

  ../../Dev/Joker/libs/PhVideo/PhVideoEncoder.cpp:360:6: error: use of undeclared identifier 'avcodec_open'
  
      if (avcodec_open(c, codec) < 0) {

• FFmpeg - Check if folder contains a matching filename with 2 different extensions and ignore both files. Process only filenames with 1 extension

  9 septembre 2019, par slyfox1186

  I need to batch convert all mkv files in a folder recursively to mp4.

  If a filename exists and matches both extensions, ignore both files and process only filenames that contain mkv, without matching mp4.

  Example : cat.mkv exists in folder with cat.mp4 = ignore both files

  Example : cat.mkv exists in folder and cat.mp4 does not = process cat.mkv to cat.mp4

  I have included a script that doesn’t work well. It processes all mkv files and mp4 files. The mp4 files throw an error as FFmpeg will not encode the same format in this manner over itself.

  As always thank you to anyone who might have a few ideas.

  UPDATE : I may have gotten it to work. I changed a few things from the original. If anyone has success or an idea to improve I’m all ears. Thanks.

  VERSION 2

  @ECHO ON
  
  SETLOCAL
  
  PROMPT $G
  
  COLOR 0A
  
  
  
  REM Set FFmpeg.exe location if not in system PATH already
  
  SET FF=C:\MAB\local64\bin-video\ffmpeg.exe
  
  
  
  REM Set MKV files root folder to recursively search
  
  SET "mkvPATH=C:\Encoding\1_Original\Test\"
  
  
  
  REM Change into mkvPATH DIR
  
  CD "C:\Encoding\1_Original\Test"
  
  
  
  REM Set temp file name
  
  SET TEMPFILE=convert_mkv.bat
  
  
  
  REM Create empty convert file
  
  COPY NUL "%TEMPFILE%" >NUL 2>&1
  
  
  
  REM ADD @ECHO OFF to top of blank convert_mkv.bat script
  
  ECHO @ECHO OFF >>"%TEMPFILE%"
  
  
  
  REM Recursively search MKV root folder
  
  FOR /R "%mkvPATH%" %%G IN (*.mkv *.mp4) DO (
  
      SET "GPATH=%%~fG"
  
      SET "GNAME=%%~nG"
  
      SETLOCAL ENABLEDELAYEDEXPANSION
  
  
  
      REM Ignore all files that have both
  
      REM extensions ".mkv" and ".mp4" in the file name
  
      IF "%%~nG.mkv"=="%%~nG.mkv" (
  
          IF NOT EXIST "%%~nG.mp4" (
  
              CALL :DO_FFmpeg "!GPATH!"
  
              IF "%%~nG.mkv"=="%%~nG.mkv" (
  
                  IF EXIST "%%~nG.mp4" (
  
                      ECHO(>>"%TEMPFILE%"
  
                  ) ELSE ENDLOCAL
  
              )
  
          )
  
      )
  
  )
  
  GOTO END
  
  
  
  REM CALL variables for use in FFmpeg's command line
  
  :DO_FFmpeg
  
  IF "%~1"=="" GOTO :END
  
  FOR %%I IN ("%~1") DO (
  
      SET "FOLDER=%%~dpI"
  
      SET "NAME=%%~nxI"
  
  )
  
  
  
  REM Export info to "%TEMPFILE% and RUN ffmpeg.exe's command line in the cmd.exe window
  
  ECHO %FF% -y -i "%~1" -ss 0 -t 300 -codec copy "%FOLDER%%~n1.mp4">>"%TEMPFILE%" && %FF% | %FF% -y -i "%~1" -ss 600 -t 30 -codec copy "%FOLDER%%~n1.mp4"
  
  
  
  :END
  
  PAUSE
  
  EXIT /B

• How can I re-encode video frames to another codec using ffmpeg ?

  24 juillet 2019, par Pedro Constantino

  I am trying to learn ffmpeg, so I started a small project where I am sending an MP4 video stream to my C# application where I want to re-encode the video to webM and send it to an icecast server.

  My icecast server is receiving the video but I am not able to reproduce it (the video time is updated each time I press play but the video doesn’t play and I only see a black frame)

  Anyone can help me ? I have no idea of what is wrong in my code.

  My code execution flow is openInput->openOutput->streamingTest

     private void openInput()
  
      {
  
          _pInputFormatContext = ffmpeg.avformat_alloc_context();
  
  
  
          var pFormatContext = _pInputFormatContext;
  
          ffmpeg.avformat_open_input(&pFormatContext, configuration.Source, null, null).ThrowExceptionIfError();
  
  
  
          ffmpeg.avformat_find_stream_info(_pInputFormatContext, null).ThrowExceptionIfError();
  
  
  
          // find the first video stream
  
          for (var i = 0; i < _pInputFormatContext->nb_streams; i++)
  
              if (_pInputFormatContext->streams[i]->codec->codec_type == AVMediaType.AVMEDIA_TYPE_VIDEO)
  
              {
  
                  pInputStream = _pInputFormatContext->streams[i];
  
                  break;
  
              }
  
  
  
          if (pInputStream == null) throw new InvalidOperationException("Could not found video stream.");
  
  
  
          _inputStreamIndex = pInputStream->index;
  
          _pInputCodecContext = pInputStream->codec;
  
  
  
          var codecId = _pInputCodecContext->codec_id;
  
          var pCodec = ffmpeg.avcodec_find_decoder(codecId);
  
          if (pCodec == null) throw new InvalidOperationException("Unsupported codec.");
  
  
  
          ffmpeg.avcodec_open2(_pInputCodecContext, pCodec, null).ThrowExceptionIfError();
  
  
  
          configuration.CodecName = ffmpeg.avcodec_get_name(codecId);
  
          configuration.FrameSize = new Size(_pInputCodecContext->width, _pInputCodecContext->height);
  
          configuration.PixelFormat = _pInputCodecContext->pix_fmt;
  
  
  
          _pPacket = ffmpeg.av_packet_alloc();
  
          _pFrame = ffmpeg.av_frame_alloc();
  
      }
  
  
  
  
  
      private bool openOutput()
  
      {
  
  
  
          int ret;
  
          _pOutputFormatContext = ffmpeg.avformat_alloc_context();
  
          fixed (AVFormatContext** ppOutputFormatContext = &_pOutputFormatContext)
  
          {
  
              ret = ffmpeg.avformat_alloc_output_context2(ppOutputFormatContext, null, "webm", configuration.Destination);
  
              if (ret < 0)
  
              {
  
                  return false;
  
              }
  
          }
  
  
  
          AVOutputFormat* out_format = ffmpeg.av_guess_format(null, configuration.Destination, null);
  
  
  
          // Configure output video stream
  
  
  
          _pOutputStream = ffmpeg.avformat_new_stream(_pOutputFormatContext, null);
  
  
  
          AVStream* pInputVideoStream = null;
  
  
  
          for (var i = 0; i < _pInputFormatContext->nb_streams; i++)
  
          {
  
              if (_pInputFormatContext->streams[i]->codec->codec_type == AVMediaType.AVMEDIA_TYPE_VIDEO)
  
              {
  
                  pInputVideoStream = _pInputFormatContext->streams[i];
  
              }
  
          }
  
  
  
          ffmpeg.avcodec_parameters_copy(_pOutputStream->codecpar, pInputVideoStream->codecpar);
  
  
  
          _pOutputStream->codecpar->codec_type = AVMediaType.AVMEDIA_TYPE_VIDEO;
  
          _pOutputStream->codecpar->codec_id = AVCodecID.AV_CODEC_ID_VP8;
  
  
  
          AVDictionary* opt_dict;
  
  
  
          ffmpeg.av_dict_set(&opt_dict, "content_type", "video/webm", 0);
  
          ffmpeg.av_dict_set(&opt_dict, "user_agent", "GCS", 0);
  
  
  
          fixed (AVFormatContext** ppOutputFormatContext = &_pOutputFormatContext)
  
          {
  
              ret = ffmpeg.avio_open2(&_pOutputFormatContext->pb, configuration.Destination, ffmpeg.AVIO_FLAG_WRITE, null, &opt_dict);
  
              if (ret < 0)
  
              {
  
                  return false;
  
              }
  
          }
  
  
  
          ret = ffmpeg.avformat_write_header(_pOutputFormatContext, null);
  
  
  
          if (ret < 0)
  
          {
  
              return false;
  
          }
  
  
  
          ffmpeg.av_dump_format(_pOutputFormatContext, 0, configuration.Destination, 1);
  
  
  
          return true;
  
      }
  
  
  
  
  
      private unsafe void streamingTest(object gggg)
  
      {
  
          isStreamUp = true;
  
  
  
          AVPacket frame = new AVPacket();
  
          AVPacket* pFrame = &frame;
  
          ffmpeg.av_init_packet(pFrame);
  
          updateState(VideoStreamStates.Streaming);
  
  
  
          try
  
          {
  
              long start_time = ffmpeg.av_gettime();
  
              DateTime lastFrame = DateTime.MinValue;
  
              while (isStreamUp)
  
              {
  
                  if (cancelationToken.IsCancellationRequested)
  
                  {
  
                      throw new TaskCanceledException();
  
                  }
  
  
  
                  try
  
                  {
  
                      int error;
  
                      isReadingFrame = true;
  
                      do
  
                      {
  
                          error = ffmpeg.av_read_frame(_pInputFormatContext, pFrame);
  
                          if (error == ffmpeg.AVERROR_EOF)
  
                          {
  
                              frame = *pFrame;
  
                              continue;
  
                          }
  
  
  
                          error.ThrowExceptionIfError();
  
                      } while (frame.stream_index != _inputStreamIndex);
  
  
  
                      isWritingFrame = true;
  
                      //frame.stream_index = _outputStreamIndex;
  
                      _pOutputCodecContext = ffmpeg.avcodec_alloc_context3(_pOutputFormatContext->video_codec);
  
  
  
                      int ret = 0;
  
                      while (ret >= 0)
  
                      {
  
                          ret = ffmpeg.avcodec_receive_packet(_pOutputCodecContext, pFrame);
  
                      }
  
  
  
                      //ffmpeg.avcodec_send_frame(_pOutputCodecContext, pFrame);
  
                      //ffmpeg.avcodec_send_packet(_pOutputCodecContext, pFrame);
  
  
  
                      ret = ffmpeg.av_write_frame(_pOutputFormatContext, pFrame);
  
  
  
                      isWritingFrame = false;
  
  
  
                      if (frame.stream_index == _inputStreamIndex)
  
                      {
  
                          if (ret < 0)
  
                          {
  
                              Console.WriteLine("Missed frame");
  
                              missedFrames++;
  
                          }
  
                          else
  
                          {
  
                              Console.WriteLine("Sent frame");
  
                              sentFrames++;
  
                          }
  
  
  
                          AVRational time_base = _pInputFormatContext->streams[_inputStreamIndex]->time_base;
  
                          AVRational time_base_q = new AVRational();
  
                          time_base_q.num = 1;
  
                          time_base_q.den = ffmpeg.AV_TIME_BASE;
  
  
  
                          long pts_time = ffmpeg.av_rescale_q(frame.dts, time_base, time_base_q);
  
                          //long pts_time = ffmpeg.av_rescale_q(frame.dts, time_base_q, time_base);
  
                          long now_time = ffmpeg.av_gettime() - start_time;
  
                          if (pts_time > now_time)
  
                              ffmpeg.av_usleep((uint)(pts_time - now_time));
  
                      }
  
                      else
  
                          Console.WriteLine("????");
  
                  }
  
                  catch (Exception ex)
  
                  {
  
                      Console.WriteLine("Erro ao enviar: " + ex.Message);
  
                  }
  
                  finally
  
                  {
  
                      ffmpeg.av_packet_unref(pFrame);
  
                  }
  
              }
  
          }
  
          catch (TaskCanceledException)
  
          {
  
              updateState(VideoStreamStates.Stopped);
  
          }
  
          catch (Exception e)
  
          {
  
              Console.WriteLine(e.Message.ToString());
  
          }
  
      }