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• avformat_open_input fails only with a custom IO context

  19 janvier 2017, par Tim

  Running into an odd issue with avformat_open_input, it is failing with :

  Invalid data found when processing input

  But this only happens when I attempt to read the file using a custom AVIOContext.

  My custom code is as follows (error checking omitted for clarity) :

  auto fmtCtx = avformat_alloc_context();
  
  auto ioBufferSize = 32768;
  
  auto ioBuffer = (unsigned char *)av_malloc(ioBufferSize);
  
  auto ioCtx = avio_alloc_context(ioBuffer,
  
                                  ioBufferSize,
  
                                  0,
  
                                  reinterpret_cast<void>(this),
  
                                  &amp;imageIORead,
  
                                  NULL,
  
                                  &amp;imageIOSeek));
  
  
  
  fmtCtx -> pb = ioCtx;
  
  fmtCtx -> flags |= AVFMT_FLAG_CUSTOM_IO;
  
  
  
  int err = avformat_open_input(&amp;fmtCtx, NULL, NULL, NULL);
  
  </void>

  imageIOSeek is never called, but properly handles the whence parameter including the AVSEEK_SIZE option. My file data is already loaded in memory, so imageIORead is trivial (returning 0 at EOF) :

  int imageIORead(void *opaque, uint8_t *buf, int buf_size) {
  
      Image *d = (Image *)buf;
  
      int rc = std::min(buf_size, static_cast<int>(d->data.size() - d->pos));
  
  
  
      memcpy(buf, d->data.data() + d->pos, rc);
  
      d->pos += rc;
  
      return rc;
  
  }
  
  </int>

  The data being read is loaded from a file on disk :

  /tmp/25.jpeg

  The following code is able to open and extract the image correctly :

  auto fmtCtx = avformat_alloc_context();
  
  int err = avformat_open_input(&fmtCtx, "/tmp/25.jpeg", NULL, NULL);

  The project is using a minified version of libavformat including only the formats we need. I don’t believe this is the cause of the problem since the file can be open and handled properly when the path is specified. I haven’t seen any configure options specifically targeting support for custom IO contexts.

  This is the image in question : 25.jpeg

• avformat/mxfenc : allow more bits for variable part in uuid generation

  14 mars 2022, par Marton Balint

  avformat/mxfenc : allow more bits for variable part in uuid generation
  Also make sure we do not change the product UID.
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavformat/mxfenc.c
  • [DH] tests/ref/fate/copy-trac4914
  • [DH] tests/ref/fate/mxf-d10-user-comments
  • [DH] tests/ref/fate/mxf-opatom-user-comments
  • [DH] tests/ref/fate/mxf-reel_name
  • [DH] tests/ref/fate/mxf-user-comments
  • [DH] tests/ref/fate/time_base
  • [DH] tests/ref/lavf/mxf
  • [DH] tests/ref/lavf/mxf_d10
  • [DH] tests/ref/lavf/mxf_dv25
  • [DH] tests/ref/lavf/mxf_dvcpro50
  • [DH] tests/ref/lavf/mxf_opatom
  • [DH] tests/ref/lavf/mxf_opatom_audio

• Rails ActionController::Live - Sends everything at once instead of async

  28 janvier 2016, par Michael B

  I have an issue with rails ActionController::Live

  In the end I want to show the progress of FFMPEG to the user, but for now I want to get this minimal example running :

  Rails media_controller.rb :

  class MediaController < ApplicationController
  
    include ActionController::Live
  
  
  
    def stream
  
      puts "stream function loaded"
  
  
  
        response.headers['Content-Type'] = 'text/event-stream'
  
        i = 0
  
        begin
  
          response.stream.write "data: 1\n\n"
  
          sleep 0.5
  
          i += 1
  
          puts "response... data: " + i.to_s
  
        end while i < 10
  
      response.stream.close
  
    end
  
  end

  Javascript :

  source = new EventSource("/test/0");
  
  source.addEventListener("message", function(response) {
  
    // Do something with response.data
  
    console.log('I have received a response from the server: ' + response);
  
  }, false);

  When I navigate to the site, there are no JavaScript Errors showing. As soon as I navigate to the site, the "stream"-Action of the MediaController gets successfully called. I can verify this, by looking at the Server-Console. It gives me the following output. After every response line, there is a 500ms delay, like expected :

  stream function loaded
  
  response... data: 1
  
  response... data: 2
  
  response... data: 3
  
  response... data: 4
  
  response... data: 5
  
  response... data: 6
  
  response... data: 7
  
  response... data: 8
  
  response... data: 9
  
  response... data: 10
  
  Completed 200 OK in 5005ms (ActiveRecord: 0.8ms)

  On the JavaScript Side, it gives me the following Output :

  (10x) I have received a response from the server: [object MessageEvent]

  But the problem is here, that it sends all these 10 Messages from the server after 5 seconds at the same time ! The expected behavior however is, that it should send me 1 message every 0.5 seconds !

  So what am I doing wrong here ? Where is the error ?