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• How to modify x264 source code to get motion search time [on hold]

  21 octobre 2017, par Yicheng Li

  I am a new member of stack overflow, I hope you guys can help me solve this problem.
  I am now using x264 with ffmpeg to encode some raw video, I was asked how much time the motion search would cost in libx264 video coding. Therefore, I need to modify the code, I tried put the clock around the switch sentence in the encoder/me.c
  clock start

  clock end
  After compiling the source code and run a test,
  it shows that the time is very small and it seems I am actually getting the time each macro block spent on motion search.

  So, how should I modify the x264 source code to get the time duration in motion search.

  Big Thanks.

• FFMPEG audio/video livestream with html5 dashjs player : time is not sync

  14 avril 2017, par Dániel Kis

  I am going to create a live video & audio stream with ffmeg with libvpx-vp9 codec, and I want to view it from html5 browser with dashjs. But when the dashjs opens the video it seatches for chunks than not yet exits. It seems that the chunk counter is running in double speed in client side.

  Here is how I create the stream :

  VP9_LIVE_PARAMS="-speed 6 -tile-columns 4 -frame-parallel 1 -threads 8 -static-thresh 0 -max-intra-rate 300 -deadline realtime -lag-in-frames 0 -error-resilient 1"
  
  TARGET_PATH="/var/www/html/live/stream"
  
  
  
  ffmpeg \
  
    -thread_queue_size 8192 \
  
    -f v4l2 -input_format mjpeg -r 30 -s 640x360 -i /dev/video0 \
  
    -thread_queue_size 16384 \
  
    -f alsa -ar 44100 -ac 2 -i hw:1,0 \
  
    -map 0:0 \
  
    -pix_fmt yuv422p \
  
    -c:v libvpx-vp9 \
  
      -s 640x360 -keyint_min 60 -g 60 ${VP9_LIVE_PARAMS} \
  
      -b:v 300k \
  
    -f webm_chunk \
  
      -header "${TARGET_PATH}/glass_360.hdr" \
  
      -chunk_start_index 1 \
  
    "${TARGET_PATH}/glass_360_%d.chk" \
  
    -map 1:0 \
  
    -c:a libvorbis \
  
      -b:a 64k -ar 44100 \
  
    -f webm_chunk \
  
      -audio_chunk_duration 2000 \
  
      -header "${TARGET_PATH}/glass_171.hdr" \
  
      -chunk_start_index 1 \
  
    "${TARGET_PATH}/glass_171_%d.chk" \

  some seconds later I call the ffmpeg again to create manifest file :

  ffmpeg \
  
    -analyzeduration 1000\
  
    -f webm_dash_manifest -live 1 \
  
    -i "${TARGET_PATH}/glass_360.hdr" \
  
    -f webm_dash_manifest -live 1 \
  
    -i "${TARGET_PATH}/glass_171.hdr" \
  
    -c copy \
  
    -map 0 -map 1 \
  
    -f webm_dash_manifest -live 1 \
  
      -adaptation_sets "id=0,streams=0 id=1,streams=1" \
  
      -chunk_start_index 1 \
  
      -chunk_duration_ms 2000 \
  
      -time_shift_buffer_depth 7200 \
  
      -minimum_update_period 7200 \
  
    "${TARGET_PATH}/glass_live_manifest.mpd"

  My server’s clock is synced to "http://time.akamai.com/?iso"

  HTML5 player :

   
  
      
  
      
  
      
  
      
  
      
  
      <code class="echappe-js">&lt;script src=&quot;https://cdn.dashjs.org/latest/dash.all.min.js&quot;&gt;&lt;/script&gt;
  
  
    
  Live broadcast
    
  
     
  
         
     
     
  &lt;script&gt;<br />
  
                  var url = &quot;glass_live_manifest.mpd&quot;;<br />
  
                  var player = dashjs.MediaPlayer().create();<br />
  
                  player.initialize(document.querySelector(&quot;#videoPlayer&quot;), url, true);<br />
  
  <br />
  
     &lt;/script&gt;
     
    
   
  

• FFmpeg for marking time video based on a reference date

  3 août 2016, par Denio Mariz

  I am trying to mark a timestamp in a video using Drawtext filter.
  FFmpeg easily marks timestamps based on localtime, gmtime or even PTS. However, I want to assign a reference time (start time) for the timestamp in order to represent the time the video was recorded (not encoded).

  Reading the documentation, I found that option "basetime" can be used for this purpose. However it seems that is not working or I am missing something.

  The command line I am using is :

  ffmpeg -y -i input.mp4 -filter_complex drawtext="fontfile=/tmp/UbuntuMono-B.ttf: fontsize=36: fontcolor=yellow: box=1: boxcolor=black@0.4: text='Wall Clock Time\: %{gmtime\:%Y-%m-%d %T}': basetime=1456007118" output.mp4

  By using basetime=1456007118", it was expected the start time was set to ’02/20/2016 20:25:18’ since 1456007118 is the UTC time for that time and date :

  date -d '02/20/2016 20:25:18' +"%s" # format MM/DD/AAAA hh:mm:ss
  
  1456007118

  However, no error is issued by FFMpeg and the video is marked with current GMT, ignoring "basetime" option.

  Any hint ?
  Thanks.

  Complete information about FFmpeg version and output is :

     ffmpeg -y -i /home/denio/Videos/Interstellar_2014_Trailer_4_5.1-1080p-HDTN.mp4 -filter_complex drawtext="fontfile=/tmp/UbuntuMono-B.ttf: fontsize=36: fontcolor=yellow: box=1: boxcolor=black@0.4: text='Wall Clock Time\: %{gmtime\:%Y-%m-%d %T}': basetime=1470226363" /tmp/x.mp4
   ffmpeg version 3.1.1 Copyright (c) 2000-2016 the FFmpeg developers
     built with gcc 5.3.1 (Ubuntu 5.3.1-14ubuntu2.1) 20160413
     configuration: --enable-libxavs --enable-bzlib --enable-libfaac --enable-libfreetype --enable-libfontconfig --enable-libmp3lame --enable-libschroedinger --enable-libspeex --enable-libvorbis --enable-libx264 --enable-libx265 --enable-libxvid --enable-zlib --enable-x11grab --enable-static --enable-pthreads --enable-gpl --enable-nonfree --enable-version3 --disable-ffserver --enable-libgsm --enable-librtmp --enable-libvpx --enable-libschroedinger --enable-libopencore-amrnb --enable-libopenjpeg
     libavutil      55. 28.100 / 55. 28.100
     libavcodec     57. 48.101 / 57. 48.101
     libavformat    57. 41.100 / 57. 41.100
     libavdevice    57.  0.101 / 57.  0.101
     libavfilter     6. 47.100 /  6. 47.100
     libswscale      4.  1.100 /  4.  1.100
     libswresample   2.  1.100 /  2.  1.100
     libpostproc    54.  0.100 / 54.  0.100
   ...
   ...