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• FFMPEG - live stream with dynamic content

  6 octobre 2019, par Arturek

  I’m trying to create a live stream with changing data in real-time on youtube.

  Let’s say I want to show the current Bitcoin price in real-time. For instance, using python and sending requests to some public APIs, I can very easily get current prices of Bitcoin. But I have no idea how to create such a live stream, which will be automatically updated with fresh data.

  I know that I can use ffmpeg to stream on youtube, but how would I change the content of my stream ? I know how to create an image every n seconds with the current price, but then I don’t know how to update my live stream with this image.

  # To make sure you know what I mean, I created a basic sample.
  
  
  
  import requests
  
  import json
  
  import time
  
  
  
  createYtLiveStream()
  
  
  
  while(True):
  
    response = requests.get('https://api.coindesk.com/v1/bpi/currentprice.json').json()
  
    price = response['bpi']['USD']['rate']
  
  
  
    # Create an image with Bitcoin price inside
  
    img = convertTextToPng(price)
  
  
  
    # Update my live stream with this new image (I don't know how to do it)
  
    updateYtLiveStream(img)
  
  
  
    time.sleep(20)

  I want to do it on Ubuntu. Can you tell me how can I do it, please ?
  Thanks.

• Is there a way to tell ffmpeg certain images are I-frames [closed]

  25 juillet 2024, par nilgirian

  I was thinking a lot about continuous zoom animation. One way to do this is to generate each frame as png and then dump it into ffmpeg and get video.

  


  If I want to cut down on processing time, I was thinking I could generate every n-frames (let's say in this case every 4 frames as an example). Then the in-between frames I'd just crop and resize that initial frame.

  


  So essentially I have an "artificial" GOP (for lack of a better name) so my first artificial GOP :

  


  

  • 0.png - fully rendered image (keyframe)

  


  • 1.png - crop and zoom of 0.png

  


  • 2.png - crop and zoom of 1.png

  


  • 3.png - crop and zoom of 2.png

  


  


  My second artificial GOP :

  


  

  • 4.png - fully rendered image (keyframe)

  


  • 5.png - crop and zoom of 4.png

  


  • 6.png - crop and zoom of 5.png

  


  • 7.png - crop and zoom of 6.png

  


  


  Rinse repeat until end of video.

  


  My question here would be is there a way to tell ffmpeg or some other tool that every 4th frame are actual I-frames, and probably shouldn't be touched.

  


  The idea being that if I want to extend the size of my artificial GOP as much as possible without losing too much detail I'd like to tell ffmpeg to not make an I-frame out of a lossy (cropped and zoomed) pngs.

  


• Correct ffmpeg scale command syntax

  10 novembre 2015, par user3132858

  I am new to ffmpeg and need some help with the correct syntax for a scale command I found here.

  Below is my code :

  $width=300;
  
  $height=200;
  
  $aspect=$width/$height;
  
  
  
  
  
  $command = "/usr/local/bin/ffmpeg -y -i 1.mp4 -vf scale=min(1\,gt(iw\,".$width.")+gt(ih\,".$height.")) * (gte(a\,".$aspect.")*".$width." + \
  
  lt(a\,".$aspect.")*((".$height."*iw)/ih)) + not(min(1\,gt(iw\,".$width.")+gt(ih\,".$height.")))*iw : \
  
  min(1\,gt(iw\,".$width.")+gt(ih\,".$height.")) * (lte(a\,".$aspect.")*".$height." + \
  
  gt(a\,".$aspect.")*((".$width."*ih)/iw)) + not(min(1\,gt(iw\,".$width.")+gt(ih\,".$height.")))*ih  -b 1200k -acodec aac -strict -2 2.mp4 ";

  Video is successfully converted however, the scaling does not go trough.

  The code is copied word for word, I only make two changes :

  • removed the " before scale word and from the end
  • replaced the $FW with $width, $FH with $height and $FA with $aspect.

  Any suggestion at what might be wrong ?