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• Direct Show Video capture performance

  23 mai 2019, par Barry Andrews

  I originally started out looking for an example of how I can use FFMPEG in c++ builder to create an application to record from usb capture device and playback video because of apparrent poor performance

  I tried Mitov components, Datastead, FFMPEGVCL and winsoft camera which use directshow but their capture performance seemed poor.

  I need to capture 1920x1080 at up to 60fps into a compressed format and play this back later at both normal speed and slow speed.

  What I found was that DirectShow itself has a number of limitations which can be improved by adding things like FFMPEG, but ultimately PC hardware, in particular the HDD and processor limit capture capability.

  1920x1080 60fps is basically the upper end for DirectShow so you need to have best performing hardware in order to achieve this sort of performance @Spektre kindly gave me examples of DirectShow using the API direct which were good for comparison with the purchased components.

  Using this and comparing to the components I found that MITOV has a major issue with regards the larger video sizes and frame rates. Using this 1920x108 30fps and 60fps can be previewed but they have a massive delay between video feed and preview (5 or 6 seconds). The other components performed similar to the API direct method with only minor variations in performance. None were able to capture and record 1920x108 60fps with any sort of compression filter without large frame drops and very jerky preview.

• How to show video (no audio) from ffmpeg via RTP in VLC ?

  15 juillet 2019, par Sagi Mann

  I’m trying to stream RTP (video only) from ffmpeg to VLC :

  ffmpeg -stream_loop -1 -i video.mp4 -vcodec copy -an -f rtp rtp://0.0.0.0:1235

  In VLC app, I do file -> "open network" and set the url to rtp ://@:1235.
  But I get an error :

  SDP required
  
  A description in SDP format is required to receive the RTP stream.
  
  Note that rtp:// URIs cannot work with dynamic RTP payload format (96).

  What am I doing wrong ? I see in ffmpeg’s output that SDP is being generated :

  SDP:
  
  v=0
  
  o=- 0 0 IN IP4 127.0.0.1
  
  s=No Name
  
  c=IN IP4 0.0.0.0
  
  t=0 0
  
  a=tool:libavformat 58.20.100
  
  m=video 1235 RTP/AVP 96
  
  b=AS:1205
  
  a=rtpmap:96 H264/90000
  
  a=fmtp:96 packetization-mode=1; sprop-parameter-sets=Z01AH9oBQBbsBEAAAAMAQAAADIPGDKg=,aO88gA==; profile-level-id=4D401F

• Ffmpeg segment doesn't show file size update in real time

  9 août 2019, par Lucas Cardoso

  I’m trying to run ffmpeg mp3 stream with segmentation for each hour. Everything is working perfectly, except for one thing : when i run the command, the file size doesn’t grow in real-time as i need, it only grows in packages of 256k.

  Is there a way to turn a "real-time mode" ?

  I’m using ubuntu 18.04 with ffmpeg 3.4.6

  This is the code i’m trying to run on linux terminal :
  ffmpeg -i http://radiocentova.conectastm.com:8363/stream -y -acodec libmp3lame -b:a 16k -ac 1 -ar 11025 -vn -strftime 1 -f segment -segment_time 3600 -flush_packets 1 @test_%Y%m%d%H%M%S+00.mp3

  Recording with segment :
  
  Recording without segment :