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• ffmpeg crashes on crossfades between 3 clips if 2 clips coming from same input file [closed]

  14 avril 2020, par Erik

  I observed that ffmpeg 4.2.2 (macOS) crashes in particular cases of crossfades between clips, if one clip comes from file 1.dv, and two clips are cut out of file 2.dv, as shown below :

  



  ffmpeg -f lavfi -i color=black:size=720x576:duration=11:rate=25 -i 1.dv -i 2.dv -filter_complex "\
    [1:v]trim=5:10,setpts=expr=PTS-STARTPTS,yadif,fade=alpha=1:d=2:st=3:type=out,setpts=expr=PTS-STARTPTS,fifo[s5];\
    [2:v]split=2[s7][s8];\
    [s7]trim=5:10,setpts=expr=PTS-STARTPTS,yadif,fade=alpha=1:d=2:type=in,fade=alpha=1:d=2:st=6:type=out,setpts=expr=PTS-STARTPTS+(3/TB),fifo[s15];\
    [s8]trim=12:17,setpts=expr=PTS-STARTPTS,yadif,fade=alpha=1:d=2:type=in,setpts=expr=PTS-STARTPTS+(6/TB),fifo[s22];\
    [0:v][s5]overlay=eof_action=repeat[s6];\
    [s6][s15]overlay=eof_action=repeat[s16];\
    [s16][s22]overlay=eof_action=repeat[s24];\
    [1:a]atrim=5:10,asetpts=expr=PTS-STARTPTS[s26];\
    [2:a]asplit=2[s27][s28];\
    [s27]atrim=5:10,asetpts=expr=PTS-STARTPTS[s30];\
    [s28]atrim=12:17,asetpts=expr=PTS-STARTPTS[s33];\
    [s26][s30]acrossfade=d=2[s31];\
    [s31][s33]acrossfade=d=2[s36]" \
     -map "[s24]" -map "[s36]" -ab 128k -acodec aac -crf 23 -movflags faststart -preset medium -tune film -vcodec libx264 -aspect 1024:576 out.mp4 -y


  



  The order makes a difference : if the two clips from 2.dv are used first and then the clip from 1.dv is appended, everything works fine. Also, if all clips are coming from different files.

  



  ffmpeg 3.4.6 (ubuntu 18.04) shows no issues in any case.

  



  A self-compiled ffmpeg version N-97322-gb1699f4 (commit 2020-04-13) works with short clips as above, but crashes if one of the two clips taken from 2.dv is getting longer. In my tests 1500 frames (64 sec) is OK, 1700 (68 sec) leads to a segmentation fault. That is, if you replace in the command line above :

  



  

  • [s7]trim=5:10... -> [s7]trim=0:68 and accordingly

  


  • [s27]atrim=5:10... -> [s27]atrim=0:68

  


  



  Interestingly, the length of the clip taken from 1.dv does not play a role.

  



  The ffmpeg output shows about 20 times :

  



  frame=    0 fps=0.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x  


  



  before it continues (seg fault case) :

  



  frame=    4 fps=0.3 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   24 fps=1.6 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   25 fps=1.5 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   34 fps=1.9 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   36 fps=2.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   39 fps=2.1 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   40 fps=2.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   40 fps=2.0 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   40 fps=1.9 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    



  



  success case :

  



  frame=    5 fps=0.4 q=0.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   42 fps=3.2 q=28.0 size=       0kB time=00:00:00.00 bitrate=N/A speed=   0x    
frame=   53 fps=3.9 q=28.0 size=       0kB time=00:00:00.36 bitrate=   2.9kbits/s speed=0.0264x    
frame=   65 fps=4.6 q=28.0 size=       0kB time=00:00:00.84 bitrate=   1.2kbits/s speed=0.0594x 
...   


  



  Slightly older versions included in the newest MacOS builds from zeranoe.com (git-2020-04-13-59e3a9a) and evermeet.cx (N-97308-g14dd0a9057-tessus, from 2020-04-12) are working nicely - also on my production cases (longer clips).

  



  Any feedback would be appreciated !

  


• Can't figure out stream mapping/commands

  11 avril 2020, par Jessie Wilson

  Help with stream mapping/commands

  



  I'm fairly new to FFMPEG. I've always encoded with GUI's. However, I've been setting up batch files to make some things easier for me !

  



  I'm taking a source file that is1080p video

  



  dts 5.1 1500 kb stream

  



  with english subs.

  



  I'm wanting to copy the video and take the DTS track, convert to AAC 2.0 at 192k and make a secondary audio track ac3 5.1 640k.

  



  This is the command i'm trying to use but no matter how many times I run it the audio channels and or bitrates get mixed up.

  



  for %%a in ("*.mkv") do ffmpeg -i "%%a" ^
-map 0:0 -map 0:1 -map 0:1 -map 0:2 ^
-c:v:0 copy ^
-c:a:0 aac -ac:0 2 -b:a:0 192k ^
-c:a:1 ac3 -ac:1 6 -b:a:1 640k ^
-c:s:0 copy ^
"\TEST%%~na.mkv"
pause


  



  Any help would be appreciated !

  


• How to run the set of commands in windows command line

  24 février 2020, par robert.little

  x264-preset is used in the second command (Cmd 2). Is it substitution or ?

  Cmd 1 :

  x264-preset:
  
  vcodec=libx264
  
  thread_type=slice
  
  slices=1
  
  profile=baseline
  
  level=32
  
  preset=superfast
  
  tune=zerolatency
  
  intra-refresh=1
  
  crf=15
  
  x264-params=vbv-maxrate=5000:vbv-bufsize=1:slice-max-size=1500:keyint=60

  Cmd 2

  $ ffmpeg -r 30 -f dshow -i video="devicename" -pix_fmt yuv420p -an -vpre
  
  x264-preset -f mpegts udp://127.0.0.1:8888

  When I run the Cmd 1 it doesn’t work. Even with the SET like :

  x264-preset:
  
  SET vcodec=libx264
  
  SET thread_type=slice
  
  SET slices=1
  
  SET profile=baseline
  
  SET level=32
  
  SET preset=superfast
  
  SET tune=zerolatency
  
  SET intra-refresh=1
  
  SET crf=15
  
  SET x264-params=vbv-maxrate=5000:vbv-bufsize=1:slice-max-size=1500:keyint=60

  Source :
  https://lists.ffmpeg.org/pipermail/ffmpeg-user/2016-January/030127.html