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• ffmpeg configuration difficulty with filter_complex and hls

  4 février 2020, par akc42

  I am trying to set up ffmpeg so that it will record from a microphone and encode the results at the same time into a .flac file for later syncing up with some video I will be making.

  The microphone is plugged into a raspberry pi (4B) and I am currently trying it with a blue yeti mic, but I think I can do the same with a focusrite scarlett 2i2 plugged in instead. However I was puzzling about how to start the server recording and decided I could do it from a web browser if I made a simple nodejs server that spawned ffmpeg as a child process.

  But then I was inspired by this sample ffmpeg command which displays (on my desktop with an graphical interface) a volume meter

  ffmpeg -hide_banner -i 'http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_30fps_normal.mp4' -filter_complex "showvolume=rate=25:f=0.95:o=v:m=p:dm=3:h=80:w=480:ds=log:s=2" -c:v libx264 -c:a aac -f mpegts - | ffplay -window_title "Peak Volume" -i -

  What if I could stream the video produced by the showvolume filter to the web browser that I am using to control the ffmpeg process (NOTE I don’t want to send the audio with this). So I tried to read up on hls (since the control device will be an ipad - in fact that is what I will record the video on), and came up with this command

  ffmpeg -hide_banner -f alsa -ac 2 -ar 48k -i hw:CARD=Microphone -filter_complex "asplit=2[main][vol],[vol]showvolume=rate=25:f=0.95:o=v:m=p:dm=3:h=80:w=480:ds=log:s=2[vid]" -map [main] -c:a:0 flac recordings/session_$(date +%a_%d_%b_%Y___%H_%M_%S).flac -map [vid] -preset veryfast -g 25 -an -sc_threshold 0 -c:v:1 libx264 -b:v:1 2000k -maxrate:v:1 2200k -bufsize:v:3000k -f hls -hls_time 4 -hls_flags independent_segments delete_segments -strftime 1 -hls_segment_filename recordings/volume-%Y%m%d-%s.ts recordings/volume.m3u8

  The problem is I am finding the documentation a bit opaque as to what happens once I have generated two streams - the main audio and a video stream, and this command throws both a warning and an error :-

  The warning is Guessed Channel Layout for Input Stream #0.0 : stereo

  and the error is

  [NULL @ 0x1baa130] Unable to find a suitable output format for 'hls'
  
  hls: Invalid argument

  What I am trying to do is set up stream labels [main] and [vol] as I split the incoming audio into two parts, then I pass [vol] through the "showvolume" filter and end up with stream [vid].

  I think I need to then use -map to specify encoding the [main] stream down to flac and writing it out to file (The file exists after I run the command although they have zero length), and use another -map to pass through to the -f hls section. But I think I have something wrong at this stage.

  Can someone help me get this command right.

• Implementing Live Streaming Webinar Architecture - Need Guidance

  21 septembre 2023, par vishnugpl

  Question : I'm working on a project to implement a live streaming webinar platform, and I'm looking for guidance on the architecture and technologies to use. I have some specific requirements and constraints, and I'd appreciate any advice or pointers on how to get started.

  


  Context :
I'm tasked with building a live streaming webinar platform from scratch for our organization. Here are some key requirements and constraints :

  


  


  1. Live Video Streaming : We need to support live video streaming for
webinars, workshops, and conferences. Low latency is crucial for
real-time interaction between presenters and attendees.

     


  


  2. Scalability : The platform should be able to handle a large number of concurrent attendees, potentially thousands or more,
without compromising performance.

     


  


  3. Security : Security is a top priority. We need to ensure that only authorized users can access the webinars, and we must protect
against unauthorized recording or distribution of the content.

     


  


  4. User Interaction : Attendees should be able to ask questions, participate in polls, and interact with presenters in real-time.

     


  


  5. Recording and Playback : We also want to provide recorded versions of past webinars for on-demand viewing (HLS).

     


  


  


  Current Tech Stack :

  


  

  • Frontend : React

  


  • Backend : Node.js with Express

  


  • Database : MongoDB

  


  • Cloud Hosting : AWS

  


  


  Questions :

  


  


  • What technologies or services are best suited for handling live video streaming with low latency ?

    


  


  • How can I ensure scalability in terms of both video streaming and handling a large number of users ?

    


  


  • What security measures should I consider to protect the content and user data ?

    


  


  • Are there any recommended frameworks or libraries for building interactive features like real-time chat and polling ?

    


  


  • What's the best approach for recording and serving on-demand webinar content ?

    


  


  


  Additional Information :

  


  


  • Budget is a consideration, so cost-effective solutions are preferred.

    


  


  • Any open-source or third-party tools that can simplify development are welcome.

    


  


  • I have experience with AWS, but I'm open to other cloud providers if they offer advantages for this project.

    


  


  


• Split HEVC video into pieces of less than 1 second

  28 septembre 2019, par Vadim

  I am trying to split 3-second HEVC video 240fps into 5 parts less than 1 second.

  Video info

  Format                      : HEVC
  
  Format/Info                 : High Efficiency Video Coding
  
  Format profile              : Main@L6@Main
  
  Codec ID                    : hvc1
  
  Codec ID/Info               : High Efficiency Video Coding
  
  Duration                    : 2 s 861 ms
  
  Bit rate                    : 84.8 Mb/s
  
  Width                       : 1 920 pixels
  
  Height                      : 1 080 pixels
  
  Display aspect ratio        : 16:9
  
  Frame rate mode             : Constant
  
  Frame rate                  : 239.760 (240000/1001) FPS
  
  Color space                 : YUV
  
  Chroma subsampling          : 4:2:0
  
  Bit depth                   : 8 bits
  
  Bits/(Pixel*Frame)          : 0.170
  
  Stream size                 : 28.9 MiB (100%)
  
  Title                       : GoPro H.265
  
  Language                    : English
  
  Encoded date                : UTC 2016-05-14 03:54:07
  
  Tagged date                 : UTC 2016-05-14 03:54:07
  
  Color range                 : Full
  
  Color primaries             : BT.709
  
  Transfer characteristics    : BT.709
  
  Matrix coefficients         : BT.709
  
  Codec configuration box     : hvcC

  FFMPEG command :

  ffmpeg -y -i output240.mp4 -c copy -segment_time 0.6 -f segment  output%0d.mp4

  But it cuts into 3 parts 1 second long each

  With h264 there is no such problem.
  If i`ll reincode h265 to h265 with parameter -x264-params keyint=1:scenecut=0

  .//ffmpeg -i testVideo.mp4 -c:v libx264 -x264-params keyint=1:scenecut=0 -c:a copy output.mp4

  It is all ok.

  Is there any option to split without encoding ?