Recherche avancée

Sur d’autres sites (9124)

• Have FFMpeg output images more consistently when reading from a stream

  11 avril 2019, par Eric Gao

  I am currently seeing an issue where FFMPEG seems to write my images in bursts. When I run the following command :

  ffmpeg -i <url> -vf fps=fps=1 -f image2 image-%d.png</url>

  I get progress updates every two seconds, at which point immediately image-(n).png and image-(n+1).png are written in quick succession.

  Is it possible to have these images output more consistently ? I would prefer to have the output speed be the same as the designated FPS (so one image per second).

  I am using a Python script to do some processing on these images and I am able to better maximize my throughput if these images came more consistently.

• Does RTMP relay server need GPU ? (NodeMediaServer)

  25 août 2020, par Hung Nguyen

  I have a curious about GPU/CPU specs of an RTMP relay server (only push) with NodeMediaServer, that use ffmpeg under the hood.

  


  I think I will receive an RTMP stream from a device and immediately push it to a CDN (that CDN will handle transcode part). So my server doesn't need to handle anything, just a relay server.

  


  So does it need to use GPU in that case ? does a cheap cloud compute (without GPU) is enough for me ?

  


  Thank you so much

• Node.js Webm live stream server : issues with tag

  10 décembre 2013, par breathe0

  I'm using Node.js as stream server to stream realtime Webm videos that is sent by FFMPEG (executed from another application, the stream is done via HTTP) and received by a webapp that uses the tag.

  This is what I'm doing : FFMPEG streams the received frames using the following command :

  ffmpeg -r 30 -f rawvideo  -pix_fmt bgra -s 640x480 
  
  -i \\.\pipe\STREAM_PIPE -r 60 
  
  -f segment  -s 240x160 -codec:v libvpx  -f webm 
  
  http://my.domain.com/video_stream.webm

  (the stream comes from an application that uses the Kinect as source and communicates with FFMPEG through a pipe, sending one frame after another)

  When the webapp connects, it receives immediately this response from the server :

  HTTP/1.1 200 OK
  
  X-Powered-By: Express
  
  content-type: video/webm
  
  cache-control: private
  
  connection: close
  
  Date: Fri, 06 Dec 2013 14:36:31 GMT

  and a Webm header (previously stored on the server, with the same resolution and frame rate of the source stream and tested as working on VLC) is immediately appended. Then the webapp starts to receive the data streamed by FFMPEG. Here is a screenshot of Mkvinfo GUI showing the fields of the header :

  

  However, even if the Network tab of the Chrome console shows that there is an actual stream of data (meaning that what is streamed is not completely garbage, otherwise the connection would be dropped), the player doesn't display anything. We tried to manually prepend our header to the dumped video received by the webapp and VLC plays it just fine, but this is not happening with the tag.

  What can cause this problem ? Are we missing something about the encoding on the FFMPEG side or we stored wrong values on the header (or they're not enough) ?

  PS : I cannot rely on an extern stream server.

  PPS : We tried the following experiments :

  • substituting the video header with the one stored in the server makes the video playable on both vlc and video tag
  • if we dump the video that is already started (without an header) and we prepend the video header stored in the server or even its original header, the video is playable in VLC but not on the tag (we're carefully prepending the header just before the beggining of the cluster).