UPDATED with info from -report

I'm new to ffmpeg.

I am trying to loop a video to a linux v4l2 device.

ffmpeg -stream_loop -1 -re -f lavfi  -i "movie=snail.mp4" -f v4l2 /dev/video4 -report

It plays the video once and then exits with the message "Invalid

[Parsed_movie_0 @ 0x56289dec9a00] EOF timestamp not reliable=N/A speed=   1x    
Error while filtering: Invalid argument
frame=  391 fps= 25 q=-0.0 Lsize=N/A time=00:00:15.64 bitrate=N/A speed=0.999x    
video:43988kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

Which argument is invalid and why?

The output of the report file generated by ffmpeg is available here: https://gist.github.com/ahoffer/7217aa0572061e7c255cf08914be53e2

  • Add -report and rerun. Share report.
    – Gyan
    Jul 28, 2020 at 5:07
  • I added -report, but it provided no additional information. ffmpeg -stream_loop -1 -re -f lavfi -i "movie=snail.mp4" -f v4l2 /dev/video4 -report
    – ahoffer
    Jul 28, 2020 at 16:04
  • 1
    It will have generated a report file in pwd. Share that.
    – Gyan
    Jul 28, 2020 at 16:21

1 Answer 1


-stream_loop is buggy in versions older than 4.1, so upgrade.

Also, stream_loop won't work with movies opened via movie filter. Use it as a direct input.

ffmpeg -stream_loop -1 -re -i "snail.mp4" -f v4l2 /dev/video4 -report
  • 1
    ffmpeg is already the newest version (7:3.4.8-0ubuntu0.2)
    – ahoffer
    Jul 30, 2020 at 0:05
  • That command sort of works. However, the framerate slowly drops from 24 FPS to about 8 FPS. Then it picks back up. It repeats the pattern indefinitely. I looking in the report file. Some kind of recursive problem? A warning of over 1000 duplicated frames? I don't know.
    – ahoffer
    Jul 30, 2020 at 0:13
  • 3
    Distro packages are very out of date. Latest ver is 4.3; you're using 3.4.8. Get a static binary - see ffmpeg.org/download.html
    – Gyan
    Jul 30, 2020 at 6:02

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