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• FFMPEG RTSP stream to MPEG4/H264 file using libx264

  16 octobre 2020, par Phi

  Heyo folks,

  



  I'm attempting to transcode/remux an RTSP stream in H264 format into a MPEG4 container, containing just the H264 video stream. Basically, webcam output into a MP4 container.

  



  I can get a poorly coded MP4 produced, using this code :

  



  // Variables here for demo
AVFormatContext * video_file_output_format = nullptr;
AVFormatContext * rtsp_format_context = nullptr;
AVCodecContext * video_file_codec_context = nullptr;
AVCodecContext * rtsp_vidstream_codec_context = nullptr;
AVPacket packet = {0};
AVStream * video_file_stream = nullptr;
AVCodec * rtsp_decoder_codec = nullptr;
int errorNum = 0, video_stream_index = 0;
std::string outputMP4file = "D:\\somemp4file.mp4";

// begin
AVDictionary * opts = nullptr;
av_dict_set(&opts, "rtsp_transport", "tcp", 0);

if ((errorNum = avformat_open_input(&rtsp_format_context, uriANSI.c_str(), NULL, &opts)) < 0) {
    errOut << "Connection failed: avformat_open_input failed with error " << errorNum << ":\r\n" << ErrorRead(errorNum);
    TacticalAbort();
    return;
}

rtsp_format_context->max_analyze_duration = 50000;
if ((errorNum = avformat_find_stream_info(rtsp_format_context, NULL)) < 0) {
    errOut << "Connection failed: avformat_find_stream_info failed with error " << errorNum << ":\r\n" << ErrorRead(errorNum);
    TacticalAbort();
    return;
}

video_stream_index = errorNum = av_find_best_stream(rtsp_format_context, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);

if (video_stream_index < 0) {
    errOut << "Connection in unexpected state; made a connection, but there was no video stream.\r\n"
        "Attempts to find a video stream resulted in error " << errorNum << ": " << ErrorRead(errorNum);
    TacticalAbort();
    return;
}

rtsp_vidstream_codec_context = rtsp_format_context->streams[video_stream_index]->codec;

av_init_packet(&packet);

if (!(video_file_output_format = av_guess_format(NULL, outputMP4file.c_str(),  NULL))) {
    TacticalAbort();
    throw std::exception("av_guess_format");
}

if (!(rtsp_decoder_codec = avcodec_find_decoder(rtsp_vidstream_codec_context->codec_id))) {
    errOut << "Connection failed: connected, but avcodec_find_decoder returned null.\r\n"
        "Couldn't find codec with an AV_CODEC_ID value of " << rtsp_vidstream_codec_context->codec_id << ".";
    TacticalAbort();
    return;
}

video_file_format_context = avformat_alloc_context();
video_file_format_context->oformat = video_file_output_format;

if (strcpy_s(video_file_format_context->filename, sizeof(video_file_format_context->filename), outputMP4file.c_str())) {
    errOut << "Couldn't open video file: strcpy_s failed with error " << errno << ".";
    std::string log = errOut.str();
    TacticalAbort();
    throw std::exception("strcpy_s");
}

if (!(video_file_encoder_codec = avcodec_find_encoder(video_file_output_format->video_codec))) {
    TacticalAbort();
    throw std::exception("avcodec_find_encoder");
}

// MARKER ONE

if (!outputMP4file.empty() &&
    !(video_file_output_format->flags & AVFMT_NOFILE) &&
    (errorNum = avio_open2(&video_file_format_context->pb, outputMP4file.c_str(), AVIO_FLAG_WRITE, nullptr, &opts)) < 0) {
    errOut << "Couldn't open video file \"" << outputMP4file << "\" for writing : avio_open2 failed with error " << errorNum << ": " << ErrorRead(errorNum);
    TacticalAbort();
    return;
}

// Create stream in MP4 file
if (!(video_file_stream = avformat_new_stream(video_file_format_context, video_file_encoder_codec))) {
    TacticalAbort();
    return;
}

AVCodecContext * video_file_codec_context = video_file_stream->codec;

// MARKER TWO

// error -22/-21 in avio_open2 if this is skipped
if ((errorNum = avcodec_copy_context(video_file_codec_context, rtsp_vidstream_codec_context)) != 0) {
    TacticalAbort();
    throw std::exception("avcodec_copy_context");
}

//video_file_codec_context->codec_tag = 0;

/*
// MARKER 3 - is this not needed? Examples suggest not.
if ((errorNum = avcodec_open2(video_file_codec_context, video_file_encoder_codec, &opts)) < 0)
{
    errOut << "Couldn't open video file codec context: avcodec_open2 failed with error " << errorNum << ": " << ErrorRead(errorNum);
    std::string log = errOut.str();
    TacticalAbort();
    throw std::exception("avcodec_open2, video file");
}*/

//video_file_format_context->flags |= AVFMT_FLAG_GENPTS;
if (video_file_format_context->oformat->flags & AVFMT_GLOBALHEADER)
{
    video_file_codec_context->flags |= CODEC_FLAG_GLOBAL_HEADER;
}

if ((errorNum = avformat_write_header(video_file_format_context, &opts)) < 0) {
    errOut << "Couldn't open video file: avformat_write_header failed with error " << errorNum << ":\r\n" << ErrorRead(errorNum);
    std::string log = errOut.str();
    TacticalAbort();
    return;
}


  



  However, there are several issues :

  



  

  1. I can't pass any x264 options to the output file. The output H264 matches the input H264's profile/level - switching cameras to a different model switches H264 level.

  


  2. The timing of the output file is off, noticeably.

  


  3. The duration of the output file is off, massively. A few seconds of footage becomes hours, although playtime doesn't match. (FWIW, I'm using VLC to play them.)

  


  



  Passing x264 options

  



  If I manually increment PTS per packet, and set DTS equal to PTS, it plays too fast, 2-3 seconds' worth of footage in one second playtime, and duration is hours long. The footage also blurs past several seconds, about 10 seconds' footage in a second.

  



  If I let FFMPEG decide (with or without GENPTS flag), the file has a variable frame rate (probably as expected), but it plays the whole file in an instant and has a long duration too (over forty hours for a few seconds). The duration isn't "real", as the file plays in an instant.

  



  At Marker One, I try to set the profile by passing options to avio_open2. The options are simply ignored by libx264. I've tried :

  



  av_dict_set(&opts, "vprofile", "main", 0);
av_dict_set(&opts, "profile", "main", 0); // error, missing '('
// FF_PROFILE_H264_MAIN equals 77, so I also tried
av_dict_set(&opts, "vprofile", "77", 0); 
av_dict_set(&opts, "profile", "77", 0);


  



  It does seem to read the profile setting, but it doesn't use them. At Marker Two, I tried to set it after the avio_open2, before avformat_write_header .

  



  // I tried all 4 av_dict_set from earlier, passing it to avformat_write_header.
// None had any effect, they weren't consumed.
av_opt_set(video_file_codec_context, "profile", "77", 0);
av_opt_set(video_file_codec_context, "profile", "main", 0);
video_file_codec_context->profile = FF_PROFILE_H264_MAIN;
av_opt_set(video_file_codec_context->priv_data, "profile", "77", 0);
av_opt_set(video_file_codec_context->priv_data, "profile", "main", 0);


  



  Messing with privdata made the program unstable, but I was trying anything at that point.
I'd like to solve issue 1 with passing settings, since I imagine it'd bottleneck any attempt to solve issues 2 or 3.

  



  I've been fiddling with this for the better part of a month now. I've been through dozens of documentation, Q&As, examples. It doesn't help that quite a few are outdated.

  



  Any help would be appreciated.

  



  Cheers

  


• ffmpeg command for concatenate two mp3 files [on hold]

  4 juin 2017, par Karami

  I am using ffmpeg for Concatenating two MP3 files together,

  I use this command :

  ffmpeg -y -i first.mp3 -i second.mp3 -filter_complex "[0:0][1:0] amix=inputs=2:duration=longest" -c:a libmp3lame output.mp3

  It works, but there is a little problem, the overlay together !

  I want first song plays, and when it finished, second file starts (in output file)

  But now they starts at the same time.

  How can i change that command, to have a output that contains first song then when the first finished, second plays ?

  Plus, I’ve tried concat command but not worked, I just can use something like what i sent.

• How to convert H264 RTP stream from PCAP to a playable video file

  21 août 2014, par yoosha

  I have captured stream of H264 in PCAP files and trying to create media files from the data. The container is not important (avi,mp4,mkv,…).
  When I’m using videosnarf or rtpbreak (combined with python code that adds 00 00 00 01 before each packet) and then ffmpeg, the result is OK only if the input frame rate is constant (or near constant). However, when the input is vfr, the result plays too fast (and on same rare cases too slow).
  For example :

  videosnarf -i captured.pcap –c
  ffmpeg -i H264-media-1.264 output.avi

  After doing some investigation of the issue I believe now that since the videosnarf (and rtpbreak) are removing the RTP header from the packets, the timestamp is lost and ffmpeg is referring to the input data as cbr.

  1. I would like to know if there is a way to pass (on a separate file ?)
     the timestamps vector or any other information to ffmpeg so the
     result will be created correctly ?
  2. Is there any other way I can take the data out of the PCAP file and play it or convert it and then play it ?
  3. Since all work is done in Python, any suggestion of libraries/modules that can help with the work (even if requires some codding) is welcome as well.

  Note : All work is done offline, no limitations on the output. It can be cbr/vbr, any playable container and transcoding. The only "limitation" I have : it should all run on linux…

  Thanks
  Y

  Some additional information :
  Since the nothing provides the FFMPEG with the timestamp data, i decided to try a different approach : skip videosnarf and use Python code to pipe the packets directly to ffmpeg (using the "-f -i -" options) but then it refuses to accept it unless I provide an SDP file...
  How do I provide the SDP file ? is it an additional input file ? ("-i config.sdp")

  The following code is an unsuccessful try doing the above :

  import time  
  
  import sys  
  
  import shutil  
  
  import subprocess  
  
  import os  
  
  import dpkt  
  
  
  
  if len(sys.argv) < 2:  
  
      print "argument required!"  
  
      print "txpcap <pcap file="file">"  
  
      sys.exit(2)  
  
  pcap_full_path = sys.argv[1]  
  
  
  
  ffmp_cmd = ['ffmpeg','-loglevel','debug','-y','-i','109c.sdp','-f','rtp','-i','-','-na','-vcodec','copy','p.mp4']  
  
  
  
  ffmpeg_proc = subprocess.Popen(ffmp_cmd,stdout = subprocess.PIPE,stdin = subprocess.PIPE)  
  
  
  
  with open(pcap_full_path, "rb") as pcap_file:  
  
      pcapReader = dpkt.pcap.Reader(pcap_file)  
  
      for ts, data in pcapReader:  
  
          if len(data) &lt; 49:  
  
              continue  
  
          ffmpeg_proc.stdin.write(data[42:])
  
  
  
  sout, err = ffmpeg_proc.communicate()  
  
  print "stdout ---------------------------------------"  
  
  print sout  
  
  print "stderr ---------------------------------------"  
  
  print err  
  
  </pcap>

  In general this will pipe the packets from the PCAP file to the following command :

  ffmpeg -loglevel debug -y -i 109c.sdp -f rtp -i - -na -vcodec copy p.mp4

  SDP file : [RTP includes dynamic payload type # 109, H264]

  v=0
  o=- 0 0 IN IP4 ::1
  s=No Name
  c=IN IP4 ::1
  t=0 0
  a=tool:libavformat 53.32.100
  m=video 0 RTP/AVP 109
  a=rtpmap:109 H264/90000
  a=fmtp:109
  packetization-mode=1 ;profile-level-id=64000c ;sprop-parameter-sets=Z2QADKwkpAeCP6wEQAAAAwBAAAAFI8UKkg==,aMvMsiw= ;
  b=AS:200

  Results :

  ffmpeg version 0.10.2 Copyright (c) 2000-2012 the FFmpeg developers
  built on Mar 20 2012 04:34:50 with gcc 4.4.6 20110731 (Red Hat
  4.4.6-3) configuration : —prefix=/usr —libdir=/usr/lib64 —shlibdir=/usr/lib64 —mandir=/usr/share/man —enable-shared —enable-runtime-cpudetect —enable-gpl —enable-version3 —enable-postproc —enable-avfilter —enable-pthreads —enable-x11grab —enable-vdpau —disable-avisynth —enable-frei0r —enable-libopencv —enable-libdc1394 —enable-libdirac —enable-libgsm —enable-libmp3lame —enable-libnut —enable-libopencore-amrnb —enable-libopencore-amrwb —enable-libopenjpeg —enable-librtmp —enable-libschroedinger —enable-libspeex —enable-libtheora —enable-libvorbis —enable-libvpx —enable-libx264 —enable-libxavs —enable-libxvid —extra-cflags=’-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector —param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC’ —disable-stripping libavutil 51. 35.100 / 51. 35.100 libavcodec 53. 61.100 / 53. 61.100 libavformat 53. 32.100
  / 53. 32.100 libavdevice 53. 4.100 / 53. 4.100
  libavfilter 2. 61.100 / 2. 61.100 libswscale 2. 1.100
  / 2. 1.100 libswresample 0. 6.100 / 0. 6.100
  libpostproc 52. 0.100 / 52. 0.100 [sdp @ 0x15c0c00] Format sdp
  probed with size=2048 and score=50 [sdp @ 0x15c0c00] video codec set
  to : h264 [NULL @ 0x15c7240] RTP Packetization Mode : 1 [NULL @
  0x15c7240] RTP Profile IDC : 64 Profile IOP : 0 Level : c [NULL @
  0x15c7240] Extradata set to 0x15c78e0 (size : 36) !error,_recognition
  separate : 1 ; 1 [h264 @ 0x15c7240] error,_recognition combined : 1 ;
  10001 [sdp @ 0x15c0c00] decoding for stream 0 failed [sdp @
  0x15c0c00] Could not find codec parameters (Video : h264) [sdp @
  0x15c0c00] Estimating duration from bitrate, this may be inaccurate
  109c.sdp : could not find codec parameters Traceback (most recent
  call last) : File "./ffpipe.py", line 26, in
  ffmpeg_proc.stdin.write(data[42 :]) IOError : [Errno 32] Broken pipe

  (forgive the mass above, the editor keep on complaining about code that is not indented OK ??)

  I’m working on this issue for days... any help/suggestion/hint will be appreciated.