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• automatically run script recording video at interval using command line and ffmpg

  29 décembre 2014, par arrie

  I’m really a beginner noob newbie command line noob. But. I’m trying to create a script that automatically starts my isight camera when turning on my mac laptop. It should create clips of about 5 seconds at an interval of 5 hours or so. (These numbers I can change of course later on if I have the basis for my script).

  So what I in fact need is (i think) a launch script, that launches a video recording script.

  Right now I’m as far as my video recording script, which is not finished : camera.sh

  #!/bin/bash
  
  
  
  FNAME=videocapture_`date +"%F_%H_%M"`.mpg
  
  echo $FNAME
  
  
  
  ffmpeg -f -t "0.20avfoundation -i "" $FNAME

  ---

  This in fact records a video when I play the script in the command line, until I tell it to quit. These videos are then named according to the date etc. But of course I want it to automatically record videos, in an already determined duration. And I just can’t seem to figure out how to make it happen. I come back to different kind of scripts using isight capture, which in fact doesn’t seem to exist anymore, and even so, I would like to stay with my own basis script just because I understand it haha.

  Hopefully someone here can help me figure this out ! Much appreciated :) Thanks !

• Is there a way to pause a script until ffmpeg finishes converting a file ?

  6 mai 2019, par Alex Dourado

  I have a python script that uploads a file to the cloud prematurely (before it finishes being converted to ogg), how can I pause the script until the conversion finishes without using something like time.sleep ?

      cmd = ("ffmpeg -i " + mp4_file + " -y -loglevel quiet -ar 16000 -ac 1 -acodec libopus -vn " + audio_file)
  
      os.popen(cmd)

• How can I make ffmpeg output proper SDP data for a data stream

  8 juillet 2021, par Shalom Crown

  I have a program based on the FFMPEG libraries, to add KLV data to a video stream. When I try to sent the output to an RTSP server (rtsp-simple-server), I get a 400 response.

  


  The apparent reason is that the SDP data for the KLV stream is missing the rtpmap.

  


  I would like to add the missing data either by setting the proper parameters in the contexts, or by specifying the data explicitly.

  


  This is the ANNOUNCE captured with Wireshark

  


  ANNOUNCE rtsp://0.0.0.0:8554/test RTSP/1.0
Content-Type: application/sdp
CSeq: 2
User-Agent: Lavf58.29.100
Content-Length: 270

v=0
o=- 0 0 IN IP4 127.0.0.1
s=No Name
c=IN IP4 127.0.0.1
t=0 0
a=tool:libavformat 58.29.100
m=video 0 RTP/AVP 96
b=AS:10000
a=rtpmap:96 H264/90000
a=fmtp:96 packetization-mode=1
a=control:streamid=0
m=application 0 RTP/AVP 97
b=AS:90
a=control:streamid=1


  


  Code fragment for initializing the data stream :

  


  AVStream* data_track = avformat_new_stream(muxer, nullptr);

if (data_track == nullptr) {
    LOG_ERROR << "failed to open data output stream";
    return nullptr;
}

muxer->oformat->video_codec = AV_CODEC_ID_H264;

AVCodec *klvEncoder = avcodec_find_encoder(AV_CODEC_ID_SMPTE_KLV);

if (klvEncoder == nullptr) {
    klvEncoder = avcodec_find_encoder(AV_CODEC_ID_BIN_DATA);
}

if (klvEncoder == nullptr) {
    klvEncoder = avcodec_find_encoder(AV_CODEC_ID_TEXT);
}

if (klvEncoder != nullptr) {
    klvEncoderContext = avcodec_alloc_context3(encoder);

    avcodec_parameters_from_context(data_track->codecpar, encoderContext);
} else {
    avcodec_parameters_copy(data_track->codecpar, pVideoStream->codecpar);
}

data_track->codecpar->codec_tag =  KLV_ID_TAG;
data_track->codecpar->codec_type = AVMEDIA_TYPE_DATA;
data_track->codecpar->codec_id = AV_CODEC_ID_SMPTE_KLV;
data_track->codecpar->bit_rate = 90000;
data_track->codecpar->format =  AV_SAMPLE_FMT_U8;
data_track->stream_identifier = KLV_ID_TAG;
data_track->id = 0x101;
data_track->time_base = video_track->time_base;
data_track->avg_frame_rate = video_track->time_base;