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• How can I use ffmpeg to stream over http

  19 juin 2014, par user3754828

  I am using the follow commands to stream to my localhost

  ffmpeg -i b.mp4 -r 60 -bufsize 1024k -vcode libtheora -qscale:v 1 -f ogg "udp://@127.0.0.1/video.ogg"
  
  
  
  ffmpeg -i b.mp4 -r 60 -bufsize 1024k -vcode libtheora -qscale:v 1 -f ogg "http://127.0.0.1/video.ogg"

  The both work very well, at least do not show any errors, but when I try play such http stream does not, it gave me error "not found"

  Can somebody help me on it ? I am complety lost in this issue...also when I try include some port, for example ffmpeg -i b.mp4 -r 60 -bufsize 1024k -vcode libtheora -qscale:v 1 -f ogg "http://127.0.0.1:8980/video.ogg" provide me input/output error...I have test the equivalent commands on vlc and is work as well.

  Thanks in advance

• Extract Video Meta Data from First Few MB on S3

  22 août 2016, par David Williams

  I have a large collection of video files on S3. I also have application servers running in AWS running a Java webapp. From those application servers, I would like to be able to extract metadata from each video file such as is provided by the Quicktime movie inspector :

  Source: /home/me/foo.mov
  
  Format: H.264, 1920x1080
  
  FPS: 29.97
  
  Data Size: 16.8 MB
  
  Data Rate: 6.70 Mbit/s

  Now, I can clearly get this information from ffmpeg :

  $ ffmpeg -i /home/me/foo.mov
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/me/foo.mov':
  
    Metadata:
  
      major_brand     : isom
  
      minor_version   : 1
  
      compatible_brands: isomavc1mp42
  
      creation_time   : 2014-06-30 22:40:08
  
    Duration: 00:00:20.02, start: 0.000000, bitrate: 6698 kb/s
  
      Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 6696 kb/s, 29.97 fps, 29.97 tbr, 30k tbn, 59.94 tbc (default)
  
      Metadata:
  
        creation_time   : 2014-06-30 22:39:09
  
        handler_name    : GPAC ISO Video Handler

  I could easily parse out the equivalent fields to the Quicktime output ! But, this would require I have the file locally. Is it possible to do this from the first few MB (or some other mechanism) of a file hosted on S3 without downloading the whole thing locally ? The goal here is to extract the same fields as the quicktime inspector from a file on S3. Any ideas ?

• How can I use libav to encode video to dvd compliant mpeg2

  18 juillet 2014, par Dave Camp

  Im new to using FFMpeg and I’d like to do the equivalent of using the command line option -f dvd but in my app, by using the libav api. In the source of FFMpeg the option sets up some parameters as

   opt_video_codec(o, "c:v", "mpeg2video");
  
   opt_audio_codec(o, "c:a", "ac3");
  
   parse_option(o, "f", "dvd", options);
  
  
  
   parse_option(o, "s", norm == PAL ? "720x576" : "720x480", options);
  
   parse_option(o, "r", frame_rates[norm], options);
  
   parse_option(o, "pix_fmt", "yuv420p", options);
  
   av_dict_set(&o->g->codec_opts, "g", norm == PAL ? "15" : "18", AV_DICT_DONT_OVERWRITE);
  
  
  
   av_dict_set(&o->g->codec_opts, "b:v", "6000000", AV_DICT_DONT_OVERWRITE);
  
   av_dict_set(&o->g->codec_opts, "maxrate", "9000000", AV_DICT_DONT_OVERWRITE);
  
   av_dict_set(&o->g->codec_opts, "minrate", "0", AV_DICT_DONT_OVERWRITE); // 1500000;
  
   av_dict_set(&o->g->codec_opts, "bufsize", "1835008", AV_DICT_DONT_OVERWRITE); // 224*1024*8;
  
  
  
   av_dict_set(&o->g->format_opts, "packetsize", "2048", AV_DICT_DONT_OVERWRITE);  // from www.mpucoder.com: DVD sectors contain 2048 bytes of data, this is also the size of one pack.
  
   av_dict_set(&o->g->format_opts, "muxrate", "10080000", AV_DICT_DONT_OVERWRITE); // from mplex project: data_rate = 1260000. mux_rate = data_rate * 8
  
  
  
   av_dict_set(&o->g->codec_opts, "b:a", "448000", AV_DICT_DONT_OVERWRITE);
  
   parse_option(o, "ar", "48000", options);

  How do these relate to the libav api ?

  The incoming video frames are at the correct resolution for pal of 720x576 in yuv420p format. Some of my params...

  pCodec = avcodec_find_encoder(AV_CODEC_ID_MPEG2VIDEO);
  
  
  
  pContext->bitrate = 48000000;
  
  pContext->width = 720;
  
  pContext->height = 576;
  
  
  
  AVRational fps = {1,25};
  
  pContext->time_base = fps;
  
  
  
  pContext->gop_size = 15;
  
  pContext->max_b_frmaes = 2;
  
  pContext->pix_fmt = AV_PIX_FMT_YUV420P;
  
  
  
  av_set_dict(&pDict,"packet_size","2048",0); // This seems to be ignored?
  
  
  
  avcodec_open2(pContext,pCodec,&pDict);

  The AVDictionary... What is the dictionary ? How does it relate the encoding process ? Is it simply a user dictionary for passing a collection of settings around your code ?

  Ultimately I’d like to be able to transcode incoming video frames that are already in the correct size and format for pal dvd and output a dvd compliant mpeg2 video ( data packets of 2048 bytes ). I understand the mpeg2 video format but I’m confused with ffmpeg params.

  Thanks !