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• Live video streaming with Node js ,HTML5, MPEG-DASH, FFMPEG and IP camera/Raspberry Pi

  12 mai 2016, par sparks

  I am a programmer but i am very new in live video streaming concepts.I need help

  What i want to accomplish

  I want to develop an online live video streaming system.The scenario is i would have a device or number of devices(raspberry pi & camera only OR ip camera only ...not sure yet) to capture the video and stream the video live in real time remotely to my web app.Multiple clients can connect to the web app and watch the video live.The key things to note here, is that these devices should be wireless(able to connect to internet and live stream the content) and also i want to eliminate the idea of manually configuring the ip adrress to local WIFI router.So simply i turn on the device and it start streaming right away to the web app.

  Infrastructure, Platforms,Browsers, Streaming methods and formats

  In the beginning i just want to stream though chrome web browser(that’s all i care about).But in the future i would build android and IOS mobile apps.So long term i would expect to be Chrome and mobile(Android & IOS platforms)
  So based on my research i learned that the client should be HTML5, streaming method MPEG-DASH(In the future add HLS), the web app will be in Node Js.I also came across Dash.js for Html5.

  My understanding of streaming based on my research

  I also came across things like FFMPEG,Dash encoder and wowza which i am not clear about.Now correct me if i am wrong, my understanding is that FFMPEG get hold of the device/camera and the content(i am not sure the format of the content at this point)and format it(i am not sure what this means in simple english) and then Dash encoder picks up and re-format the content to MPEG-DASH format, which produces MPD and then Dash.js client uses MPD to display the video to the browser.

  QUESTIONS

  1. First correct me if i am wrong based on my understanding above or
     clarify for me.Also I am not sure of where the wowza streaming
     engine come into play. Do i even need it ?

  2. I am not sure of the devices to use between Raspberry pi with camera
     module/ Or IP Wifi camera by itself.I know with raspberry pi
     connected to internet you can set up all the necessary programs and
     stream the video to web app directly(not sure about quality and
     performance) but I am not sure about Wifi camera.Is it possible to
     connect to the wifi camera remotely from the web app programatically
     without opening the wifi router portal manually or i should stick
     with Raspbery Pi ?

  3. For raspberry Pi would i be able to connect it with high quality
     picture IP camera/web cam ? (The point here to get the best picture
     through raspbery Pi)

     My expectations

     Better performance and quality would be great.But i know live streaming is not easy so i am willing to compromise performance to a point but not quality.

  Thank you in advance, Anything will be appreciated.I know this is a lot so take your time :)

• calculating vmaf using ffmpeg

  26 avril 2022, par david

  I am trying to calculate VMAF using FFmpeg. for this, I installed ffmepg-python and used the following code in python.

  


  from ffmpeg_quality_metrics import FfmpegQualityMetrics as ffqm
a=ffqm("E:/6.mp4","E:/6_fast.mp4").calc(["vmaf"])


  


  it produced a dic and contains PSNR, SSIM, and some other things besides VMAF for each frame. but I just need to have VMAF. I have a folder of mp4 files and I need to calculate VMAF for each of these videos( and their reference videos) and then save a text file for each of them that contains VMAF value for each frame. before, I used the following python code for calculating PSNR and I need something like this for VMAF, but I could not find anything. could you please help me with this issue ? Thanks

  


  subprocess.call(['ffmpeg.exe', '-i', pname1, '-i', pname2, '-lavfi', f'psnr=stats_file={n}', '-f', 'null', '-'])


  


  how can I save these VMAF values in a dic into a text file ? It also time consuming. is it reasonalbe ?

  


• vp9/x86 : use explicit register for relative stack references.

  25 janvier 2014, par Ronald S. Bultje

  vp9/x86 : use explicit register for relative stack references.
  Before this patch, we explicitly modify rsp, which isn’t necessarily
  
  universally acceptable, since the space under the stack pointer might
  
  be modified in things like signal handlers. Therefore, use an explicit
  
  register to hold the stack pointer relative to the bottom of the stack
  
  (i.e. rsp). This will also clear out valgrind errors about the use of
  
  uninitialized data that started occurring after the idct16x16/ssse3
  
  optimizations were first merged.
  

  • [DH] libavcodec/x86/vp9itxfm.asm