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• ffmpeg transcoding.c problems about 'dimensions not set'

  11 mars 2016, par Park Han Wool

  guys

  I try to solve this problem in transcoding.c example about FFMPEG. but I don’t know how to approach...

  this is my problem

  [libx264 @ 00000000022c7120] dimensions not set

  Cannot open video encoder for stream #0

  Error occurred : Invalid argument

  here is my code to fix the transcoding.c example a little bit

  static int open_output_file(const char *filename)
  
  {
  
      AVStream *out_stream;
  
      AVStream *in_stream;
  
      AVCodecContext *dec_ctx, *enc_ctx;
  
      AVCodec *encoder;
  
      int ret;
  
      unsigned int i;
  
  
  
      ofmt_ctx = NULL;
  
  
  
      avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, filename);
  
  
  
      if (!ofmt_ctx) {
  
          av_log(NULL, AV_LOG_ERROR, "Could not create output context\n");
  
          return AVERROR_UNKNOWN;
  
      }
  
  
  
  
  
  
  
      for (i = 0; i < ifmt_ctx->nb_streams; i++) {
  
  
  
          in_stream = ifmt_ctx->streams[i];
  
  
  
          out_stream = avformat_new_stream(ofmt_ctx, NULL);
  
  
  
          if (!out_stream) {
  
              av_log(NULL, AV_LOG_ERROR, "Failed allocating output stream\n");
  
              return AVERROR_UNKNOWN;
  
          }
  
  
  
  
  
          dec_ctx = avcodec_alloc_context3(in_stream->codec->codec);
  
          enc_ctx = avcodec_alloc_context3(out_stream->codec->codec);
  
  
  
  
  
          printf("codec name : %s \n", avcodec_get_name(enc_ctx->codec_id));
  
  
  
  
  
          if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO || dec_ctx->codec_type == AVMEDIA_TYPE_AUDIO) {
  
  
  
  
  
  
  
              /* in this example, we choose transcoding to same codec */
  
              encoder = avcodec_find_encoder(dec_ctx->codec_id);
  
  
  
  
  
              //encoder = avcodec_find_encoder(AV_CODEC_ID_H264);
  
  
  
              if (!encoder) {
  
                  av_log(NULL, AV_LOG_FATAL, "Necessary encoder not found\n");
  
                  return AVERROR_INVALIDDATA;
  
              }
  
  
  
  
  
  
  
              /* In this example, we transcode to same properties (picture size,
  
              * sample rate etc.). These properties can be changed for output
  
              * streams easily using filters */
  
              if (dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO) {
  
  
  
  
  
                  enc_ctx->height = dec_ctx->height;
  
                  enc_ctx->width = dec_ctx->width;
  
                  enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;
  
  
  
                  /* take first format from list of supported formats */
  
                  //enc_ctx->pix_fmt = encoder->pix_fmts[0];
  
                  enc_ctx->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
                  /* video time_base can be set to whatever is handy and supported by encoder */
  
                  enc_ctx->time_base = dec_ctx->time_base;
  
  
  
              }
  
  
  
              else {
  
                  enc_ctx->sample_rate = dec_ctx->sample_rate;
  
                  enc_ctx->channel_layout = dec_ctx->channel_layout;
  
                  enc_ctx->channels = av_get_channel_layout_nb_channels(enc_ctx->channel_layout);
  
  
  
                  /* take first format from list of supported formats */
  
                  enc_ctx->sample_fmt = encoder->sample_fmts[0];
  
                  enc_ctx->time_base.num = 1;
  
                  enc_ctx->time_base.den = enc_ctx->sample_rate;
  
              }
  
  
  
  
  
              /* Third parameter can be used to pass settings to encoder */
  
              ret = avcodec_open2(enc_ctx, encoder, NULL);
  
  
  
  
  
  
  
              if (ret < 0) {
  
                  cout << "ret<0" << endl;
  
                  av_log(NULL, AV_LOG_ERROR, "Cannot open video encoder for stream #%u\n", i);
  
                  return ret;
  
              }
  
  
  
  
  
          }
  
          else if (dec_ctx->codec_type == AVMEDIA_TYPE_UNKNOWN) {
  
              av_log(NULL, AV_LOG_FATAL, "Elementary stream #%d is of unknown type, cannot proceed\n", i);
  
              return AVERROR_INVALIDDATA;
  
          }
  
          else {
  
              /* if this stream must be remuxed */
  
              ret = avcodec_copy_context(ofmt_ctx->streams[i]->codec, ifmt_ctx->streams[i]->codec);
  
              if (ret < 0) {
  
                  av_log(NULL, AV_LOG_ERROR, "Copying stream context failed\n");
  
                  return ret;
  
              }
  
          }
  
  
  
          if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
  
              enc_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
      }
  
  
  
      av_dump_format(ofmt_ctx, 0, filename, 1);
  
  
  
      if (!(ofmt_ctx->oformat->flags & AVFMT_NOFILE)) {
  
          ret = avio_open(&ofmt_ctx->pb, filename, AVIO_FLAG_WRITE);
  
          if (ret < 0) {
  
              av_log(NULL, AV_LOG_ERROR, "Could not open output file '%s'", filename);
  
              return ret;
  
          }
  
      }
  
  
  
      /* init muxer, write output file header */
  
      ret = avformat_write_header(ofmt_ctx, NULL);
  
      if (ret < 0) {
  
          av_log(NULL, AV_LOG_ERROR, "Error occurred when opening output file\n");
  
          return ret;
  
      }
  
  
  
      return 0;
  
  
  
  }

  what part I didn’t check....

  and why avcodec_open2 does not work...

• Using ffmpeg library

  29 juillet 2014, par DAVIDBALAS1

  Thx all for helping <3

  So, I have downloaded the ffmpeg library, imported it to eclipse, added it as a library to my android application and tried to use it, it doesn’t work.

  Step by step :

  • Downloaded this file : https://github.com/guardianproject/android-ffmpeg-java
  • Extracted it to an empty folder.
  • At Eclipse, "import" and then I have selected this empty folder.
  • Right click at my project, properties, android, added the ffmpeg library.

  • At my on create I used this code(just for checking) :

    ffmpeg -t 30 -i inputfile.mp3 -acodec copy outputfile.mp3

  But I get a lot of errors :

  Multiple markers at this line
  
  - Syntax error on token(s), misplaced 
  
   construct(s)
  
  - Syntax error on token "inputfile", delete this 
  
   token
  
  - Syntax error on token "30", delete this token
  
  - Syntax error on token ".", ; expected

  Can you see my problem ?

• A ffmpeg command method into a webjob

  2 juillet 2017, par Fearhunter

  I am new with Azure Webjobs. I made an ffmpeg function to slice a stream into separate mp4 files :

  public Process SliceStream()
  
  {
  
      var url = model_s.Url;
  
      var cuttime = model_s.Cuttime;
  
      var output = model_s.OutputPath;
  
      return Process.Start(new ProcessStartInfo
  
      {
  
          FileName = "ffmpeg.exe",
  
          Arguments = $"-i \"{url}\" -c copy -flags +global_header -f segment -segment_time \"{cuttime}\" -segment_format_options movflags=+faststart -reset_timestamps 1 \"{output}\"",
  
          UseShellExecute = false,
  
          RedirectStandardOutput = true
  
      });
  
  }

  The var properties are the variables for the user input on the front-end. I want to scheduled this method into a webjob. How can I achieve this ? I saw an article on google

  https://zimmergren.net/getting-started-with-building-azure-webjobs-timer-jobs-for-your-office-365-sites/

  Need I just follow these steps to achieve my goal ? Or must I add some C# code to achieve this ?