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• How can I have ffmpeg receive both video and audio over RTP ?

  23 mai 2018, par KallDrexx

  I am trying to instruct FFMPEG to receive h264 video and aac audio via RTP using out of band session initialization.

  To do that I have the following local SDP :

  v=0
  
  o=sb
  
  s=-
  
  t=0 0
  
  c=IN IP4 127.0.0.1
  
  m=video 12100 RTP/AVP 96
  
  a=rtpmap:96 H264/90000
  
  m=audio 12101 RTP/AVP 97
  
  a=rtpmap:97 MPEG4-GENERIC/44100/2

  When I load ffmpeg with :

  ffmpeg -loglevel debug -protocol_whitelist "file,rtp,udp" -i .\test.sdp -strict -2 test.flv

  I get the following error :

  [udp @ 0000022d7fdafe80] bind failed: Error number -10048 occurred
  
  [AVIOContext @ 0000022d7fd84900] Statistics: 154 bytes read, 0 seeks
  
  .\test.sdp: Invalid data found when processing input

  Confused by that error code I loaded it up on a Linux VM and the bind error I got was Address already in use.

  I tried changing both of those port numbers all around and kept getting that error. Finally I removed one of the media streams from the SDP so it ONLY had video or ONLY had audio and no binding error occurred.

  How can I get ffmpeg to bind to multiple RTP ports for RTP ingestion ?

• ffmpeg : remove dead call to av_parser_change()

  21 mars 2018, par James Almer

  ffmpeg : remove dead call to av_parser_change()
  It's been a noop for years, and it's been argued that in-band headers
  
  should not be forcedly removed without the user's explicit request.
  Also, as the FIXME line stated, this is a job for a bitstream filter
  
  like extract_extradata, remove_extradata, dump_extradata, and
  
  filter_units.
  Signed-off-by : James Almer <jamrial@gmail.com>
  

  • [DH] fftools/ffmpeg.c
  • [DH] fftools/ffmpeg.h

• Using FFMPEG to make HLS clips from H264

  21 novembre 2017, par Tyler Brooks

  I am using a Hi35xx camera processor from HiSilicon. It is an Arm9 with a video pipeline bolted on the side. At one end of the pipeline is the CMOS sensor. At the other end is a H264 encoder. When I turn on the pipeline, the encoder outputs H264 NAL packets like this :

  frame0: <sps>,<pps>,<sei>,<key frame="frame">
  
  frame1: <delta frame="frame">
  
  frame2: <delta frame="frame">
  
  ...
  
  frameN: <delta frame="frame">
  
  frameN+1: <sps>,<pps>,<sei><key frame="frame">
  
  frameN+2: <delta frame="frame">
  
  frameN+3: <delta frame="frame">
  
  ...
  
  etc.
  
  </delta></delta></key></sei></pps></sps></delta></delta></delta></key></sei></pps></sps>

  I am turning that into HLS clips by doing the following (pseudo code for clarity) :

  av_register_all();
  
  avformat_network_init();
  
  
  
  avformat_alloc_output_context2(&ctx_out, NULL, "hls", "./foo.m3u8");
  
  
  
  strm_out = avformat_new_stream(ctx_out, NULL);
  
  
  
  codec_out = strm_out->codecpar;
  
  codec_out->codec_id = AV_CODEC_ID_H264;
  
  codec_out->codec_type = AVMEDIA_TYPE_VIDEO;
  
  codec_out->width = encoder_width;
  
  codec_out->height = encoder_height;
  
  codec_out->bit_rate = encoder_bitrate;
  
  codec_out->codec_tag = 0;
  
  
  
  avformat_write_header(ctx_out, NULL);
  
  
  
  while(get_packet_from_pipeline_encoder(&encoder_packet)) {
  
    AVPacket pkt;
  
    av_init_packet(&pkt);
  
    pkt.stream_index = 0;
  
  
  
    pkt.dts = AV_NOPTS_VALUE;
  
    pkt.pts = AV_NOPTS_VALUE;
  
    pkt.duration = (1000000/FRAMERATE);    // frame rate in microseconds
  
  
  
    pkt.data = encoder_packet.data;
  
    pkt.size = encoder_packet.size;
  
  
  
    if (is_keyframe(&encoder_packet)) {
  
      pkt.flags |= AV_PKT_FLAG_KEY;
  
    }
  
  
  
    av_write_frame(ctx_out, &pkt);
  
  }
  
  
  
  av_write_trailer(ctx_out);
  
  avformat_free_context(ctx_out);

  This seems to work fine except that the resulting HLS frame rate is not right. Of course, this happens because I am not setting the pts/dts stuff correctly and ffmpeg lets me know that. So I have two quetions :

  1. Am I going about this right ?
  2. How can I set the pts/dts stuff correctly ?

  The encoder is giving me packets and I am submitting them as frames. Those <sps>, <pps> and <sei></sei></pps></sps> packets are really out of band data and don’t really have a timestamp. How can I submit them correctly ?