Recherche avancée

Sur d’autres sites (10231)

• What ffmpeg filters can I use to achieve shrinking a video and keeping original aspect ratio ?

  3 août 2020, par sivano

  I am trying to do some specific video editing with ffmpeg and am lacking the correct terminology to describe it (and thus read online how to achieve it). Can someone help describe this using standard (ffmpeg/video editing) terminology ?

  


  The below describes it verbosely, and you can see it visually at the end (this was done manually for one image).

  


  I have a video with aspect ratio 1280x720. At some point in the video, I want to shrink the video diagonally (i.e. maintaining aspect ratio) so that it only takes up half the original width (i.e. 640) and then pad what is left with black. The purpose of this is to then overlay some other image on the left hand of the modified video.

  


  Before


  


  After


  


  Thank you

  


• ffmpeg filter_complex multiple overlays - why are they not syncing properly

  28 décembre 2023, par howdood

  I'm setting up live streaming using three overlaid inputs in ffmpeg. O:v is a webcam directly connected to the streaming box (a headless linux box) while 2:v and 3:v are ultra-low latency UDP streams from two remote R-Pis.

  


  The filter_complex argument I'm using (that works, with all three video inputs perfectly in sync) is
[0:v] fifo [v1] ;[2:v] fifo [v2] ; [3:v] fifo [v3] ;[v1]setpts=PTS-STARTPTS[sync1] ;[v2]setpts=PTS-STARTPTS[sync2] ; [v3]setpts=PTS-STARTPTS+5/TB [sync3] ;[sync1][sync2] overlay=x=W-w:y=H-h [out1] ;[out1][sync3] overlay=x=0:y=H-h [vfinal]

  


  Two questions about this :

  


  


  1. Why am I having to add +5/TB to [sync3] via setpts (in bold above) ? If I omit that, [3:v] is synced in to the stream noticeably ahead of the other two inputs. My best guess is that this may be to compensate for the processing time of the first overlay [sync1][sync2] which is introducing extra latency into that part of the stream. Is that right ?

     


  


  2. Importantly - the value of the extra pts compensation has to be dialed in by hand and will be specific to the underlying hardware used. Is there a way of getting ffmpeg to calculate this automatically so I don't have to worry about keeping in dialed in, in production ?

     


  


  


  Thanks for reading ! I'm at the limit of the ffmpeg docs here...

  


• inotifywait -m does not process more than 1 file after long running process

  2 mai 2022, par Yllier123

  I have a script that detects files on close_write and runs an 5 minute process on them. These files are written to the directory in batches of up to 100. The issue is that inotifywait only detects the first file in the batch and does not process the subsequent files unless they are removed from the directory by hand and put back. Here is my script :

  


  #!/bin/bash

inotifywait -r -e close_write -e moved_to --format "%f" $TARGET -m | while read file
    do
        if [[ "$file" =~ .*mp4$ ]]; then
            echo "Detected $file"
            /usr/bin/python3 LongRunningProgram.py -i $TARGET/$file -o $PROCESSED -u $UPLOADPATH -c $C
        fi
    done


  


  it is maintained by a systemctl service written like so :

  


  [Unit]
Description=Description
After=network.target

[Service]
Type=idle
user=pi
WorkingDirectory=/home/pi
ExecStart=/bin/bash /home/pi/notify.sh OutPath C
Restart=on-failure

[Install]
WantedBy=multi-user.target


  


  I am confused as to why it only seems to recognize the first file but not subsequent files when run like this, however if I replace the long running program with sleep 300 it seems to work fine.