Recherche avancée

Sur d’autres sites (5386)

• FPS from RTSP stream info does not match actual framerate

  17 mai 2021, par Krapow

  I have a 25FPS RTSP stream coming from an IP-camera. I can successfully display the video stream. But when analyzing the stream with ffmpeg (ffprobe actually), I observe fewer frames per second rate :

  


  $ ffprobe -rtsp_transport tcp -i rtsp://camera_ip:554/stream -select_streams v:0 -show_frames -show_entries frame=coded_picture_number,pkt_pts_time -of csv=p=0
Stream #0:0: Video: h264 (Main), yuvj420p(pc, bt709, progressive), 640x480, 25 fps, 25 tbr, 90k tbn, 50 tbc
0.400000,0
0.080000,1
0.120000,2
0.200000,3
0.240000,4
0.320000,5
0.360000,6
0.440000,7
0.480000,8
0.560000,9
0.600000,10
0.680000,11
0.720000,12
0.800000,13
0.840000,14
0.920000,15
0.960000,16
1.040000,17
1.080000,18
1.160000,19
1.200000,20
1.280000,21
1.320000,22
1.400000,23
1.440000,24
1.520000,25
1.560000,26
1.640000,27
1.680000,28
1.760000,29
1.800000,30
1.880000,31
1.920000,32
2.000000,33


  


  We can clearly see the 80ms gap between some of the frames, resulting in a 16fps stream.

  


  I have observed the same framerate issue with GStreamer (printing information in the rtpjitterbuffer indicates the frame gap is sometimes 80ms and sometimes 40ms). But the weird thing is, I encountered the same issue with an HDMI-RJ45 decoder, and I doubt the same issue comes from 2 different devices.
I didn't get much more informations using -loglevel debug or trace.
Does anybody have an idea about what is going wrong in the stream ?

  


  (I used ffprobe 4.2.3 and the last "2021-05-09-git-8649f5dca6-full_build-www.gyan.dev" with the same results, and GStreamer 1.16.2 with a pipeline like "urisourcebin ! h264depay ! h264parse ! fakesink")

  


  EDIT : The camera skipping of frames was caused by the activation of a third stream in the options. I find it really weird that it skips exactly the same frames every seconds. However, I still haven't found the cause of the downrate on my RTSP encoder.
Anyway, this was actually hardware related and not software related.

  


• Where can I find ffmpeg codecs for Windows Chromium (h.264, AAC, mp3..) ?

  21 décembre 2013, par masfrost

  In previous version you could copy files from google Chrome's folders and paste them into the Chromium files, but that doesn't work anymore. Apparently all the files have been replaced by 1 file ffmpegsumo.dll, copying that from Chrome changes nothing.

  I downloaded codecs for Chromium on linux, but I find it weird that there's no way to get them for Windows.

  Why don't they just add h.264 to chromium now that cisco made it royalty free ?

• Unable to get the original quality after resizing in ffmpeg

  24 septembre 2018, par Sabha

  I am trying to resize a high res video into 480x ??? and with to maintain aspect ratio and also without losing quality. I wish to maintain the original quality of the video. I tried this command line but it loses quality.

  ffmpeg -i a.mp4 -filter:v scale=480:-1 -c:a copy b.mp4

  I got some filters and options from google search such as -qscale,-sameq etc but it is not working.

  Can you please tell me the exact command ?

  Thanks

  EDIT : I also need to place two videos one below the other and wish to know if there is any such option in ffmpeg coz I cannot find anything on google.