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• ffmpeg fails to open a WAV file - "too short LIST tag" [closed]

  5 janvier 2024, par brad

  I have a WAV file exported in FL Studio 21.2.2 on Win10, which ffmpeg/ffprobe cannot open.

  


  When running :

  


  ffprobe -v error -show_format -print_format json -hide_banner -i "path/to/file.wav


  


  This exception is thrown :

  


  [wav @ 0x132704440] too short LIST tag
[in#0 @ 0x132704340] Error opening input: Invalid data found when processing input


  


  Here's a screenshot of the file metadata in macOS

  


  Since i'm not able to open the file with ffmpeg, i can't correct/remove the metadata. Any ideas what I can do ? File is available upon request. Thanks !

  


• Could not open encoder using ffmpeg C APi for MOV format

  22 juin 2016, par lupod

  Context

  I am writing a program for doing some video processing on an input file. I wrote two classes for handling the "reading/writing frames" part that essentially wrap the functions of ffmpeg. These classes may be instantiated by providing an input and output file name, and in their constructor I initialize everything that is needed (or at least I hope so).

  This are the two routines that are called inside the constructors :

  // InputVideoHandler.cpp
  
  void InputVideoHandler::init(char* name) {
  
    streamIndex = -1;
  
    int numStreams;
  
  
  
    if (avformat_open_input(&formatCtx, name, NULL, NULL) != 0)
  
      throw std::exception("Invalid input file name.");
  
  
  
    if (avformat_find_stream_info(formatCtx, NULL)<0)
  
      throw std::exception("Could not find stream information.");
  
  
  
    numStreams = formatCtx->nb_streams;
  
  
  
    if (numStreams < 0)
  
      throw std::exception("No streams in input video file.");
  
  
  
    for (int i = 0; i < numStreams; i++) {
  
      if (formatCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
  
        streamIndex = i;
  
        break;
  
      }
  
    }
  
  
  
    if (streamIndex < 0)
  
      throw std::exception("No video stream in input video file.");
  
  
  
    // find decoder using id
  
    codec = avcodec_find_decoder(formatCtx->streams[streamIndex]->codec->codec_id);
  
    if (codec == nullptr)
  
      throw std::exception("Could not find suitable decoder for input file.");
  
  
  
    // copy context from input stream
  
    codecCtx = avcodec_alloc_context3(codec);
  
    if (avcodec_copy_context(codecCtx, formatCtx->streams[streamIndex]->codec) != 0)
  
      throw std::exception("Could not copy codec context from input stream.");
  
  
  
    if (avcodec_open2(codecCtx, codec, NULL) < 0)
  
      throw std::exception("Could not open decoder.");
  
  
  
    codecCtx->refcounted_frames = 1;
  
  }
  
  
  
  // OutputVideoBuilder.cpp
  
  void OutputVideoBuilder::init(char* name, AVCodecContext* inputCtx) {
  
    if (avformat_alloc_output_context2(&formatCtx, NULL, NULL, name) < 0)
  
      throw std::exception("Could not determine file extension from provided name.");
  
  
  
    codec = avcodec_find_encoder(inputCtx->codec_id);
  
    if (codec == nullptr) {
  
      throw std::exception("Could not find suitable encoder.");
  
    }
  
  
  
    codecCtx = avcodec_alloc_context3(codec);
  
    if (avcodec_copy_context(codecCtx, inputCtx) < 0)
  
      throw std::exception("Could not copy output codec context from input");
  
  
  
    codecCtx->time_base = inputCtx->time_base;
  
  
  
    if (avcodec_open2(codecCtx, codec, NULL) < 0)
  
      throw std::exception("Could not open encoder.");
  
  
  
    stream = avformat_new_stream(formatCtx, codec);
  
    if (stream == nullptr) {
  
      throw std::exception("Could not allocate stream.");
  
    }
  
  
  
    stream->id = formatCtx->nb_streams - 1;
  
    stream->codec = codecCtx;
  
    stream->time_base = codecCtx->time_base;
  
  
  
    av_dump_format(formatCtx, 0, name, 1);
  
    if (!(formatCtx->oformat->flags & AVFMT_NOFILE)) {
  
      if (avio_open(&formatCtx->pb, name, AVIO_FLAG_WRITE) < 0) {
  
        throw std::exception("Could not open output file.");
  
      }
  
    }
  
  
  
    if (avformat_write_header(formatCtx, NULL) < 0) {
  
      throw std::exception("Error occurred when opening output file.");
  
    }
  
  
  
  }

  As you see, for the Init function of the output handler I require that an AVCodecContext must be provided. In my code, I pass to the constructor the AVCodecContext that is stored in the input handler and that was previously created.

  Question :

  The two functions work fine when I test my program with some video formats, like .mpg or .avi. When I try to process .mov/.mp4 files, however, my code throws the exception that I labeled "Could not open encoder." in OutputVideoBuilder::Init(). Why is this happening ? I read from the General documentation of ffmpeg that that format should be supported as well by ffmpeg. I am assuming that I am doing something wrong in my code, which I do not completely understand because it was created by trying to adapt the tutorials of the documentation to my specific case. Also for this reason, any comments on things that are useless or things that are missing will be greatly appreciated.

• Google Chrome dropping support for H.264, will support only open web codecs in the future

  11 janvier 2011, par Basil Gohar — Announcements, chrome, encumbrance, freedom, google, html5, mpeg-la, software patents, theora, vp8, webm

  In an understated announcement on the Chromium blog, going forward, Google Chrome will drop support for the encumbered H.264 video codec and will support only VP8 (through WebM) & Theora video natively. This is great news for the open web, … Read more (...)