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• Transcode to opus by Fluent-ffmpeg or ffmpeg from command line

  14 juillet 2017, par shamaleyte

  My purpose is to transcode a webm file into opus file.
  It works just fine as the following ;

  ffmpeg -i input.webm -vn -c:a copy output.opus

  But the generated opus file always starts from 4rd or 5th seconds when I play it. It seems like that the first seconds are lost. Any idea why it happens ?

  >ffmpeg -i x.webm -vn -c:a copy x1.opus
  
  ffmpeg version N-86175-g64ea4d1 Copyright (c) 2000-2017 the FFmpeg 
  
  developers
  
  built with gcc 6.3.0 (GCC)
  
  configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid -
  
  -enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-
  
  avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls 
  
  --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-
  
  libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-
  
  libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb -
  
  -enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --
  
  enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --
  
  enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab -
  
  -enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-
  
  libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-
  
  libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
  
    libavutil      55. 63.100 / 55. 63.100
  
    libavcodec     57. 96.101 / 57. 96.101
  
    libavformat    57. 72.101 / 57. 72.101
  
    libavdevice    57.  7.100 / 57.  7.100
  
    libavfilter     6. 90.100 /  6. 90.100
  
    libswscale      4.  7.101 /  4.  7.101
  
    libswresample   2.  8.100 /  2.  8.100
  
    libpostproc    54.  6.100 / 54.  6.100
  
  Input #0, matroska,webm, from 'x.webm':
  
    Metadata:
  
    encoder         : libwebm-0.2.1.0
  
    creation_time   : 2017-06-19T20:50:21.722000Z
  
  Duration: 00:00:32.33, start: 0.000000, bitrate: 134 kb/s
  
  Stream #0:0(eng): Audio: opus, 48000 Hz, mono, fltp (default)
  
  Stream #0:1(eng): Video: vp8, yuv420p(progressive), 640x480, SAR 1:1 DAR 
  
  4:3, 16.67 fps, 16.67 tbr, 1k tbn, 1k tbc (default)
  
  Output #0, opus, to 'x1.opus':
  
  Metadata:
  
  encoder         : Lavf57.72.101
  
  Stream #0:0(eng): Audio: opus, 48000 Hz, mono, fltp (default)
  
  Metadata:
  
    encoder         : Lavf57.72.101
  
  Stream mapping:
  
  Stream #0:0 -> #0:0 (copy)
  
  Press [q] to stop, [?] for help
  
  size=     114kB time=00:00:32.33 bitrate=  28.8kbits/s speed=3.22e+003x
  
  video:0kB audio:111kB subtitle:0kB other streams:0kB global headers:0kB 
  
  muxing overhead: 2.152229%

  It is jumping from 0 to 4th second .
  Please take a look at this screencast.
  https://www.screenmailer.com/v/52IXnpAarHavwJE

  This is the sample video file that I tried to transcode : https://drive.google.com/open?id=0B2sa3oV_Y3X_ZmVWX3MzTlRPSmc

  So I guess the transcoding starts right at the point that the voice comes in, why is that ?

• FFmpeg : Not able to decode H264 encoded file using Ffmpeg library functions [on hold]

  13 août 2019, par Vikas Singh

  I am trying to decode a H264 encoded attached file using FFmpeg
  library functions...

  avformat_open_input() 
  
  av_read_frame() 
  
  avcodec_send_packet() 
  
  avcodec_recieve_frame() .

  File :- https://drive.google.com/open?id=1t_0nh-6jm5d3VpWIRVd25wYKNvt4Yjo7
  When i decode it using-

  ffplay frame1.bin

  command it gives me the output image.
  But when i am trying to decode it using the C program it gives error on avcodec_recieve_frame(). It returns -11.

  Part of my code i am using for decoding purpose..

  uint8_t *inbuf = (uint8_t*) malloc(sizeof(uint8_t)*(INBUF_SIZE + AV_INPUT_BUFFER_PADDING_SIZE));
  
    uint8_t *data;
  
  
  
                size_t   data_size;
  
                int ret=0;
  
  
  
                /* set end of buffer to 0 (this ensures that no overreading happens for damaged MPEG streams) */
  
                memset(inbuf + INBUF_SIZE, 0, AV_INPUT_BUFFER_PADDING_SIZE);
  
  
  
  
  
         pkt = av_packet_alloc();
  
  
  
         if (!pkt)
  
                exit(1);
  
  
  
         /* find the video decoder */
  
  
  
         codec = avcodec_find_decoder(AV_CODEC_ID_H264);
  
         if (!codec) {
  
                fprintf(stderr, "Codec not found\n");
  
                exit(1);
  
         }
  
  
  
         parser = av_parser_init(codec->id);
  
         if (!parser) {
  
                fprintf(stderr, "parser not found\n");
  
                exit(1);
  
         }
  
  
  
         c = avcodec_alloc_context3(codec);
  
         if (!c) {
  
                fprintf(stderr, "Could not allocate video codec context\n");
  
                exit(1);
  
         }
  
  
  
         /* open it */
  
         if (avcodec_open2(c, codec, NULL) < 0) {
  
                fprintf(stderr, "Could not open codec\n");
  
                exit(1);
  
         }      
  
        char *filename = "D:\\frame1.bin";
  
         fopen_s(&f, filename, "rb");
  
         printf("\n%s", filename);
  
         if (!f) {
  
                fprintf(stderr, "Could not open %s\n", filename);
  
                exit(1);
  
         }
  
  
  
  
  
         frame = av_frame_alloc();
  
         frameRGB = av_frame_alloc();
  
         if (!frame || !frameRGB) {
  
                fprintf(stderr, "Could not allocate video frame\n");
  
                exit(1);
  
         }                   
  
         while (!feof(f)) {
  
                           //Reading complete data in one go.. INBUF_SIZE=FILE_SIZE 
  
                             data_size = fread(inbuf, 1, INBUF_SIZE, f);
  
  
  
                              if (!data_size)
  
                                    break;
  
  
  
                             /* use the parser to split the data into frames */
  
                             data = inbuf;
  
                             while (data_size > 0) {
  
  
  
                                    ret = av_parser_parse2(parser, c, &pkt->data, &pkt->size,
  
                                           data, data_size, AV_NOPTS_VALUE, AV_NOPTS_VALUE, 0);
  
                                    if (ret < 0) {
  
                                           fprintf(stderr, "Error while parsing\n");
  
                                           goto even;
  
                                    }
  
  
  
  
  
  
  
                                                  data += ret;
  
                                                  data_size -= ret;
  
  
  
  
  
                                    if (pkt->size)
  
                                    {
  
  
  
                                           AVCodecContext *dec_ctx = c;
  
                                           char buf[1024];
  
                                           int ret_send_pkt, ret_recv_frame;
  
                                           struct SwsContext *sws_ctx = NULL;
  
  
  
  
  
                                           ret_send_pkt = avcodec_send_packet(dec_ctx, pkt);
  
                                           if (ret_send_pkt < 0) {
  
                                                  fprintf(stderr, "Error sending a packet for decoding\n");
  
                                                  //exit(1);
  
                                                  goto even;
  
                                           }
  
  
  
                                           while (ret_send_pkt >= 0) {
  
                                                  ret_recv_frame = avcodec_receive_frame(dec_ctx, frame);
  
                                                  if (ret_recv_frame == AVERROR(EAGAIN) || ret_recv_frame == AVERROR_EOF)
  
                                                  {
  
                                                         //fprintf(stderr, "Error during decoding11\n");
  
                                                         goto even;                                                   
  
                                                  }
  
                                                  else if (ret_recv_frame < 0) {
  
                                                         fprintf(stderr, "Error during decoding\n");
  
                                                         //exit(1);
  
                                                         goto even;
  
                                                  }
  
  
  
  
  
                                           }
  
                                    even:  ;
  
                                    }
  
  
  
                             }
  
  
  
                       }

• Why A .FLAC File Converted by FFMPEG Cause File Explorer Unresponse on Windows 10 [closed]

  20 juillet 2022, par Alex King

  My File Explorer Always showing "Working on it."
I've tried many resolutions.
First,I disconnect my NAS drive. seems fine.
I test many times on diffirient windows 10/11 versions.
I thought it was SMB problem on windows. But i was wrong.

  


  Today I'm using FFMPEG convert .wav to .flac.

  


  .\ffmpeg.exe -i $Source -c:a flac $Dest 


  


  Just simple like this. Blow my computer up.

  


  Even worse, explorer.exe crash after I'm trying to open FF output folder.

  


  It's not the poblem from "Quick access" or "Search Index".

  


  I'm now 100% percent confirm the flac files that ffmpeg made will cause file explorer crash.

  


  I can't solve it without knowing the reason.

  


  Might related to audio file tag vorbis ?

  


  This is my FFMPEG info

  


  ffmpeg version n5.0.1-4-ga5ebb3d25e-20220428 Copyright (c) 2000-2022 the FFmpeg developers

built with gcc 11.2.0 (crosstool-NG 1.24.0.533_681aaef)