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• avfilter/zoompan : add in_time variable

  19 juin 2020, par exwm

  avfilter/zoompan : add in_time variable
  Currently, the zoompan filter exposes a 'time' variable (missing from docs) for use in
  
  the 'zoom', 'x', and 'y' expressions. This variable is perhaps better named
  
  'out_time' as it represents the timestamp in seconds of each output frame
  
  produced by zoompan. This patch adds aliases 'out_time' and 'ot' for 'time'.
  This patch also adds an 'in_time' (alias 'it') variable that provides access
  
  to the timestamp in seconds of each input frame to the zoompan filter.
  
  This helps to design zoompan filters that depend on the input video timestamps.
  
  For example, it makes it easy to zoom in instantly for only some portion of a video.
  
  Both the 'out_time' and 'in_time' variables have been added in the documentation
  
  for zoompan.
  Example usage of 'in_time' in the zoompan filter to zoom in 2x for the
  
  first second of the input video and 1x for the rest :
  
      zoompan=z='if(between(in_time,0,1),2,1):d=1'
  V2 : Fix zoompan filter documentation stating that the time variable
  
  would be NAN if the input timestamp is unknown.
  V3 : Add 'it' alias for 'in_time. Add 'out_time' and 'ot' aliases for 'time'.
  
  Minor corrections to zoompan docs.
  Signed-off-by : exwm <thighsman@protonmail.com>
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/vf_zoompan.c

• ffmpeg x11grab moov atom not found

  30 mars 2021, par Jintor

  2 FFMPEG process

  


  (1) generating a ffmpeg x11grab to a .mp4
(2) take the .mp4 and restream it simultaneously to multiple rtmp endpoints

  


  ISSUE the generated file in (1) have this error "moov atom not found"

  


  This is the command that generate (1) :

  


  ffmpeg -re -y -f x11grab -draw_mouse 0 -framerate 30 
-video_size $RESOLUTION -i :$DISPLAY_NUM -c:a aac -c:v libx264 
-movflags +faststart -preset ultrafast -crf 28 -refs 4 -qmin 4 
-pix_fmt yuv420p -filter:v fps=30 file.mp4


  


  in the (2) => when I try to ffmpeg -i file.mp4 output somewhere : I get "moov atom not found" so the (2) can't read or open (1).

  


  What I'm I missing

  


  in (1) -movflags +faststart doesn't seem to fix the issue

  


  ••••••• EDIT : more details on the context ••••••

  


  I'm using openvidu : webrtc with kurento and coturn.

  


  The record feature creates a .mp4 on the fly as the chat is going on.

  


  To start the recording, there is an API call i can make to my server and it automatically stops when all users leaves the chatroom OR do an other api call to stop. see composed video in this link https://docs.openvidu.io/en/2.17.0/advanced-features/recording/

  


  openvidu have also webhooks.

  


  My problem is not how to stop ffmpeg, but getting FFMPEG to encode while the mp4 or other is being generated "on the fly".

  


  There is 2 options :

  


  OPTION 1 : individual => 1 .webm per camare => this .webm ffmpeg can restream as hls or RTMP => it's working.

  


  OPTION 2 : ** but the issue is with "Composed" video => it's using ffmpeg to x11grab the session... but it's mp4 without moov ato, so ffmpeg don't do anything with this.

  


  see the composed.sh script here
https://github.com/OpenVidu/openvidu/blob/master/openvidu-server/docker/openvidu-recording/scripts/composed.sh

  


• ffmpeg - overlay multiple fading texts with different colors

  18 novembre 2017, par Abc123

  I have problem with this ffmpeg command, it works fine if the fading text is in white font color, but if I change the fontcolor to something else (for example black), the fading text will not appear, any ideas ?

  ffmpeg -i ./based_video/480/clip3.mp4 -filter_complex "color=black:100x100[c]; [c][0]scale2ref[ct][mv0]; \
  
  [ct]setsar=1,split=3[t1][t2][t3]; \
  
  [t1]drawtext=fontfile=/usr/share/fonts/truetype/roboto/Roboto-Bold.ttf:text='\$30,000.0':fontsize=40:fontcolor=white,split[text1][alpha1]; \
  
  [text1][alpha1]alphamerge,fade=t=in:st=1:d=1:alpha=1,fade=t=out:st=5:d=1:alpha=1[txta1]; \
  
  [t2]drawtext=fontfile=/usr/share/fonts/truetype/roboto/Roboto-Bold.ttf:text='\$30,000.0':fontsize=40:fontcolor=white,split[text2][alpha2]; \
  
  [text2][alpha2]alphamerge,fade=t=in:st=1:d=1:alpha=1,fade=t=out:st=5:d=1:alpha=1[txta2]; \
  
  [t3]drawtext=fontfile=/usr/share/fonts/truetype/roboto/Roboto-Bold.ttf:text='\$30,000.0':fontsize=40:fontcolor=white,split[text3][alpha3]; \
  
  [text3][alpha3]alphamerge,fade=t=in:st=1:d=1:alpha=1,fade=t=out:st=5:d=1:alpha=1[txta3]; \
  
  [mv0][txta1]overlay=x='100':y='200':shortest=1[mv1]; \
  
  [mv1][txta2]overlay=x='300':y='200':shortest=1[mv2]; \
  
  [mv2][txta3]overlay=x='500':y='200':shortest=1" \
  
  -c:v libx264 -c:a copy ./output_video/testnew-clip3-output.mp4

  full log is here :
  https://docs.google.com/document/d/1y9Dnn0Df75J8P_hZ6LjHTX2dk-8z97UnTjlX8dnc0v0/edit?usp=sharing

  Thanks in advance