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• How to add suffix to duplicate filenames output by ffmpeg in Windows batch file ?

  27 septembre 2015, par Nick Hope

  I have written a script in Sony Vegas Pro that outputs an edit list of video files (E :\editlist.txt) of the following form, where the 2nd item is the start timecode and the 3rd item is the length :

  E:\folder\file1a.mp4 16.8835333 17.5175
  
  E:\folder\file2a.mp4 6.0393666 12.1454666
  
  E:\folder\file3a.mp4 0 3.5368667
  
  E:\folder\file3a.mp4 5.1344667 9.3033
  
  E:\folder\file3a.mp4 12.1224623 19.483756

  I have also cobbled together a Windows batch script that uses ffmpeg to trim those files and re-wrap them in a .mov container.

  for /F "tokens=1,2,3 delims= " %%F in (E:\editlist.txt) do ffmpeg.exe -ss "%%G" -i "%%F" -c copy -t "%%H" "%%~dF%%~pF%%~nF.mov"

  However because some files originate from the same source file (in this case, file3a.mp4), the trimmed files have duplicate names.

  I would like to create a script that detects duplicates and adds an incremental single-digit suffix to the output file names, before the file extension. In this case the 5 output files should be file1a.mov, file2a.mov, file3a.mov, file3a1.mov and file3a2.mov.

  I have had a go but I have no experience of writing Windows batch files, so the following effort fails and is probably very wrong, but hopefully it shows what I am trying to achieve (it was loosely based on an answer to this question) :

  for /F "tokens=1,2,3 delims= " %%F in (E:\editlist.txt)
  
      set counter=0
  
      if exist "%%~dF%%~pF%%~nF.mov" (
  
      set counter=%counter%+1
  
      do ffmpeg.exe -ss "%%G" -i "%%F" -c copy -t "%%H" "%%~dF%%~pF%%~nF%counter%.mov"
  
  ) else do ffmpeg.exe -ss "%%G" -i "%%F" -c copy -t "%%H" "%%~dF%%~pF%%~nF.mov"

  I would greatly appreciate it if someone could help me get this working. Thanks !

• H264 decoding using ffmpeg

  18 mai 2019, par Kindermann

  I’m trying to decode a video stream with ffmpeg library, that’s how I do it basically :

  void video_decode(const char *filename)
  
  {
  
      AVCodec *codec;
  
      AVCodecContext *c= NULL;
  
      int frame_count=0;
  
      FILE *f;
  
      AVFrame *frame;
  
      uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
  
      AVPacket avpkt;
  
      av_init_packet(&avpkt);
  
      memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
  
      printf("Decoding video file...\n");
  
      /* find the h264 video decoder */
  
      codec = avcodec_find_decoder(AV_CODEC_ID_H264);
  
      c = avcodec_alloc_context3(codec);
  
      c->bit_rate = 400000;
  
      c->width = 1920;
  
      c->height = 1080;
  
  
  
      if (avcodec_open2(c, codec, NULL) < 0) {
  
          fprintf(stderr, "Could not open codec\n");
  
          exit(1);
  
      }
  
      frame = av_frame_alloc();
  
      for (;;) {
  
          avpkt.size = fread(inbuf, 1, INBUF_SIZE, f);         
  
      if (avpkt.size == 0)
  
              break;
  
          avpkt.data = inbuf;
  
          while(avpkt.size > 0){
  
  
  
          int len, got_frame;
  
              len = avcodec_decode_video2(c, frame, &got_frame, &avpkt);          
  
          if (len < 0) {
  
                  fprintf(stderr, "Errr while decding frame %d\n", frame_count);
  
                  exit (1);
  
              }
  
              if (got_frame) {
  
                  //Print out frame information..
  
          }
  
              if (avpkt.data) {
  
                  avpkt.size -= len;
  
                  avpkt.data += len;
  
              }
  
      }               
  
      }  
  
  }

  But I got the following outputs :

  Decoding video file...
  
  [h264 @ 0x303c040] decode_slice_header error
  
  [h264 @ 0x303c040] decode_slice_header error
  
  [h264 @ 0x303c040] decode_slice_header error
  
  [h264 @ 0x303c040] no frame!
  
  Errr while decding frame 0

  Obviously the initiation of codec was incomplete. Do you have experience with h264 api ? Any help would be appreciated.

• H264 decoding using ffmpeg

  14 juillet 2016, par Kindermann

  I’m trying to decode a video stream with ffmpeg library, that’s how I do it basically :

  void video_decode(const char *filename)
  
  {
  
      AVCodec *codec;
  
      AVCodecContext *c= NULL;
  
      int frame_count=0;
  
      FILE *f;
  
      AVFrame *frame;
  
      uint8_t inbuf[INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE];
  
      AVPacket avpkt;
  
      av_init_packet(&avpkt);
  
      memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
  
      printf("Decoding video file...\n");
  
      /* find the h264 video decoder */
  
      codec = avcodec_find_decoder(AV_CODEC_ID_H264);
  
      c = avcodec_alloc_context3(codec);
  
      c->bit_rate = 400000;
  
      c->width = 1920;
  
      c->height = 1080;
  
  
  
      if (avcodec_open2(c, codec, NULL) < 0) {
  
          fprintf(stderr, "Could not open codec\n");
  
          exit(1);
  
      }
  
      frame = av_frame_alloc();
  
      for (;;) {
  
          avpkt.size = fread(inbuf, 1, INBUF_SIZE, f);         
  
      if (avpkt.size == 0)
  
              break;
  
          avpkt.data = inbuf;
  
          while(avpkt.size > 0){
  
  
  
          int len, got_frame;
  
              len = avcodec_decode_video2(c, frame, &got_frame, &avpkt);          
  
          if (len < 0) {
  
                  fprintf(stderr, "Errr while decding frame %d\n", frame_count);
  
                  exit (1);
  
              }
  
              if (got_frame) {
  
                  //Print out frame information..
  
          }
  
              if (avpkt.data) {
  
                  avpkt.size -= len;
  
                  avpkt.data += len;
  
              }
  
      }               
  
      }  
  
  }

  But I got the following outputs :

  Decoding video file...
  
  [h264 @ 0x303c040] decode_slice_header error
  
  [h264 @ 0x303c040] decode_slice_header error
  
  [h264 @ 0x303c040] decode_slice_header error
  
  [h264 @ 0x303c040] no frame!
  
  Errr while decding frame 0

  Obviously the initiation of codec was incomplete. Do you have experience with h264 api ? Any help would be appreciated.