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• Capture live video from a camera on a computer and using ffmpeg

  21 juin 2013, par Devendra

  I am trying to capture live video from a camera on a computer and using ffmpeg as an encoder, send this video for live streaming to a IIS server.

  Here is what I did :

  1. Captured feed from webcam using video4linux2 and ffmpeg

  2. Installed x264 for a h.264 codec

  3. Used muxer feature in ffmpeg, as described on this link -
     http://www.ffmpeg.org/ffmpeg-formats.html#Muxers
     to generate ismv file locally
     Command -
     ffmpeg -f video4linux2 -r 25 -s 640x480 -i /dev/video0 -b:v 661k -c:v libx264 -movflags isml+frag_keyframe+empty_moov -f ismv test.ismv

  4. Now to get the complete system in place (live capture from webcam and live streaming on IIS server), I want ffmpeg to generate this ffmpeg file on a publish point. here is the command I used
     ffmpeg -f video4linux2 -r 25 -s 640x480 -i /dev/video0 -b:v 661k -c:v libx264 -movflags isml+frag_keyframe+empty_moov -f ismv http://www.MY-SERVER/PushToPublishPoint/Test.isml

  as described at this link :

  http://www.unified-streaming.com/support/documentation/content-delivery/publishing-points/
  http://www.unified-streaming.com/support/documentation/content-encoding/encoders/

  It shows some video is being generated, but I cannot see any activity at the server.

  When I use wireshark to look at the packet info, there are many packet transfers between pc and the server.

  I have kept publishing point in IDLE state, STARTING state to see if that is the problem, but no progress there as well.
  I think I am unable to establish communication with the server. Pls help.

  Any help would be appreciated.

  Thanks

• delay between subtitles and video/audio hls ffmpeg videojs

  16 juillet 2020, par Maxou

  I use ffmpeg to convert video to hls format (m3u8) and I use videojs to read this video. But I have a problem, subtitles appeared 1.4 seconds before the real timestamp.

  


  I execute this command to extract video, audio and subtitles :

  


  ffmpeg -i [file] -map 0:1 -c:a aac -ar 48000 -b:a 320k -hls_time 2 -hls_segment_filename audio/1/seq-%d.ts audio/1/320kbit.m3u8 -map 0:2 -c:a aac -ar 48000 -b:a 320k -hls_time 2 -hls_segment_filename audio/2/seq-%d.ts audio/2/320kbit.m3u8 -map 0:s:0 -f webvtt sub.vtt -map 0:v:0 -vf scale=1920:-2 -c:v h264 -profile:v main -g 48 -keyint_min 48 -crf 20 -sc_threshold 0 -b:v 5000k -maxrate 5350k -bufsize 7500k -hls_time 2 -hls_segment_filename video/1080p/seq-%d.ts video/1080p/5000k.m3u8


  


  And this command to convert substile to hls format

  


  ffmpeg -i sub.vtt -f segment -segment_time 2 -segment_list_size 0 -segment_list my-hero/subtitles/sub.m3u8 -segment_format webvtt -scodec copy my-hero/subtitles/seq-%d.vtt


  


  And then I create a playlist file to gather all of that

  


  #EXTM3U
#EXT-X-VERSION:3

#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio-group",LANGUAGE="fre",NAME="Français",DEFAULT=YES,AUTOSELECT=YES,URI="audio/1/128k.m3u8"
#EXT-X-MEDIA:TYPE=AUDIO,GROUP-ID="audio-group",LANGUAGE="jpn",NAME="Japonais",DEFAULT=NO,AUTOSELECT=YES,URI="audio/2/128k.m3u8"

#EXT-X-MEDIA:TYPE=SUBTITLES,GROUP-ID="subs",NAME="Français",DEFAULT=yes,AUTOSELECT=YES,FORCED=NO,LANGUAGE="fr",URI="subtitles_fr.m3u8"

#EXT-X-STREAM-INF:BANDWIDTH=5000000,RESOLUTION=1920x1080,SUBTITLES="subs",AUDIO="audio-group"
video/1080p/5000k.m3u8


  


  I don't see the problem so if anyone have an idea :/

  


• ffmpeg append video with different dimensions

  21 avril 2020, par friendlygiraffe

  I am cropping and adding subtitles to a video using the following :

  



  ffmpeg -i inputfile.mov -lavfi "crop=720:720:280:360,subtitles=subs.srt:force_style='OutlineColour=&H100000000,BorderStyle=3,Outline=1,Shadow=0,MarginV=20,Fontsize=18'" -crf 1 -c:a copy output.mov

  



  I have another video called credits.mp4 which has the same dimensions as the output.mov (after cropping). Can I do this during the above process, or would I have to use something like concat afterwards ?

  



  Using bash in Terminal on a Mac