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• How to run ffmpeg command from the client side ?

  12 janvier 2017, par Debraj Biswas

  I am trying to make an online examination portal. When students start the exam, their webcam will start automatically and record the stream live and store in the server. Invigilators will either watch the students live or they can watch the saved live streams later.

  After many research on various technologies I came across this link. It uses Node JS with websockets and ffmpeg. I ran the ffmpeg command and it streamed the live video successfully.

  But the problem is, in order to live stream, the students have to have ffmpeg installed in their system and they should run the command directly from the terminal. So how can I change this ? The students will live stream from their browser, because this is a web portal. If we put this command in a PHP script, then the command will run at the server side. But client side command should run in this case. How can I run command from client side ?

  Any suggestions will be helpful.

• Streaming from Icecast to Facebook Live with ffmpeg on Ubuntu 16.04

  14 janvier 2017, par Matthieu

  I have a webradio streamed by Liquidsoap+Icecast on a DigitalOcean droplet (Ubuntu 16.04), and I want to combine this audio stream with a simple jpeg image with ffmpeg, transform it to a video stream and send it to Facebook live.

  Facebook Live specifications :

  Video Format :

  We accept video in maximum 720p (1280 x 720) resolution, at 30 frames
  per second. (or 1 key frame every 2 seconds). You must send an I-frame
  (keyframe) at least once every two seconds throughout the stream..
  Recommended max bit rate is 4000 Kbps. Titles must be less than 255
  characters otherwise the stream will fail. The Live API accepts H264
  encoded video and AAC encoded audio only.

  Video Length :

  240 minute maximum length, with the exception of continuous live (see
  above). 240 minute maximum length for preview streams (either through
  Live dialog or publisher tools). After 240 minutes, a new stream key
  must be generated.

  Advanced Settings :

  Pixel Aspect Ratio : Square. Frame Types : Progressive Scan. Audio
  Sample Rate : 44.1 KHz. Audio Bitrate : 128 Kbps stereo. Bitrate
  Encoding : CBR.

  And the ffmpeg command I tried :

  ffmpeg -loop 1 -i radio-background.jpg -thread_queue_size 20480 -i http://localhost:8000/radio -framerate 30 -r 30 -acodec aac -strict -2 -c:v libx264 -strict experimental -b:a 128k -pix_fmt yuvj444p -x264-params keyint=60 -b:v 256k -minrate 128k -maxrate 512k -bufsize 768k -f flv 'rtmp://rtmp-api.facebook.com:80/rtmp/'

  This is actually working, as Facebook receives the live video and allows me to publish it. But I can’t figured out why there is a lag almost every 2 or 3 seconds. I asked different people to watch the test video, and everyone gets the same problem : every 2 or 3 seconds the playing "freezes" for half a second and seems to load the video, I even can see the loading icon spinning on the screen.

  I tried different combinations of values for the following options : -thread_queue_size / -b:v / -minrate / -maxrate / -bufsize. Nothing seems to produce any change.

  Video streaming is new for me, I’m not really confortable with the options listed before, so I think I’m missing something here...

  Also, note that the icecast audio stream perfectly works, and according to DigitalOcean graphs, the server is not overloaded. So I think my ffmpeg command is wrong.

  What ffmpeg parameters would be working for that case ?

• Extract just the audio link from a youtube video without converting

  19 janvier 2017, par kamron shaw

  I know there are hundreds of sites to convert youtube video to mp3. Most of them do it by first downloading the video and then converting it to mp3(or any other audio format) on their server using youtube-dl, ffmpeg or similar programs.

  What I want to know is, is there any way I can just extract the audio link for any youtube video ? I don’t know if it’s possible but I saw a couple of websites doing it .

  First Website : Openaisearch.com
  This website simply gives a download link for the audio(getting it from youtube videos). I searched for a song and saw the download url, it looked something like this :

  https://redirector.googlevideo.com/videoplayback?source=youtube&requiressl=yes&clen=3814013&upn=dzwY9aUVYME&lmt=1469875393441562&expire=1484854959&mime=audio%2Fmp4&nh=IgpwcjAxLnNlYTA5Kg01Mi45NS4yMTYuMTAy&itag=140........... 

  I believe that this is not done by first downloading and converting the video to audio format(Correct me if I am wrong).
  Although the file which gets downloaded after using this link is without any extension, but adding ".m4a" at the end of downloaded file does the work.

  Second Website : http://keepvid.com/ ?url=https ://www.youtube.com/watch?v=PT2_F-1esPk

  Again similar website with similar audio link. You can check by visiting the URL and see link of audio files.

  Any idea how these websites get that "googlevideo.com" link ? Do they scrap the youtube video links or something ?

  Thanks.