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• FFMPEG combining MP4 videos with same encoding not working, only showing first video

  13 avril 2020, par Ayudh

  My mp4 videos have the same encoding : h264

  



  I know because I ran this command on them :

  



  ffprobe -v error -select_streams v:0 -show_entries stream=codec_name -of default=noprint_wrappers=1:nokey=1 a.mp4

  



  Now I combine them using the following command :

  



  ffmpeg -loglevel quiet -f concat -safe 0 -i video-list.txt -c copy video-final.mp4

  



  my video-list.txt file looks like this :

  



  file 'a.mp4'
file 'b.mp4'
file 'c.mp4'


  



  Now the video-final.mp4 which is the combined video actually has duration which is equal to the sum of its' component videos and also is quite larger in size. The issue is that when I play the video, it only plays the first video then stops.

  



  What's going on here ? Any insight would be appreciated.

  



  I've looked at : ffmpeg : Combine/merge multiple mp4 videos not working, output only contains the first video and the answers suggested there are the ones I'm using : specifically, concating from a text file containing the component videos.

  


• FFMPEG XFade Transition

  21 juin 2022, par UserErrorLoL

  I am attempting to use xfade transitions to link multiple video files but I have noticed that the transition does not finish in most cases. If I set the duration to 1 second, it may get 1/4 through the screen before instantly starting the next video. Does this have something to do with my ffmpeg settings like framerate ? My current call is ffmpeg -i inputs 1-10 -aspect 16:9 -filter complex video_fades -map [final] -c:v libx264 -preset ultrafast -crf 28 out.mp4

  


  The inputs are all 1920x1080 60fps videos and the video fades graph is

  


  


  [0:v][1:v]xfade=transition=wipeleft:duration=2.000000:offset=32.700[v01] ;
[v01][2:v]xfade=transition=squeezeh:duration=2.000000:offset=125.400[v12] ;
[v12][3:v]xfade=transition=slideup:duration=2.000000:offset=218.100[v23] ;
[v23][4:v]xfade=transition=slidedown:duration=2.000000:offset=310.800[v34] ;
[v34][5:v]xfade=transition=wipedown:duration=2.000000:offset=403.500[v45] ;
[v45][6:v]xfade=transition=zoomin:duration=2.000000:offset=496.200[v56] ;
[v56][7:v]xfade=transition=slidedown:duration=2.000000:offset=588.900[v67] ;
[v67][8:v]xfade=transition=dissolve:duration=2.000000:offset=681.600[v78] ;
[v78][9:v]xfade=transition=slidedown:duration=2.000000:offset=774.300[v89] ;
[v89]format=pix_fmts=yuv420p[final]

  


  


  Has anyone else had this problem and knows how to fix it ?

  


• ffmpeg UDP stream incomplete using WEBM (VP9)

  21 janvier 2018, par DerLars

  I’m trying to encode a raw (YUV) video into VP9 and to stream it with ffmpeg via UDP.

  Sender command :

  ffmpeg -f rawvideo -pix_fmt yuv420p -s:v 352x288 -r 25 -i ReferenceVideo_200Frames.yuv -c:v libvpx-vp9 -lossless 1 -f webm udp ://localhost:1337

  Receiver command : (started first)

  ffmpeg -i udp ://localhost:1337 -vcodec copy ReferenceVideo_200Frames_Streamed.webm

  The testvideo used for this has exactly 200 Frames.

  The final output of the sender is :
  frame= 200 fps= 14 q=0.0 Lsize= 7918kB time=00:00:07.96 bitrate=8147.3kbits/s speed=0.574x
  video:7912kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead : 0.064364%

  But as soon as the sender finishes, the receiver gets stuck at : frame= 181 fps= 13 q=-1.0 size= 5226kB time=00:00:07.20 bitrate=5945.5kbits/s speed=0.531x

  The final streamed video is now incomplete.

  So my question is : What am I doing wrong that the stream is incomplete ? Did anyone face this issue too and was able to fix it ?

  Many thanks in advance.