[FFmpeg-user] Problem with changing options at runtime with a command

Alex Christoffer Rasmussen ac at omnivox.dk
Sat Jul 3 14:47:13 EEST 2021

i am trying to change options in the crop filter at runtime with a command

this it my test command:
./ffmpeg -hide_banner -y -f dshow -rtbufsize 128M -i video="Cam Link 4K"
-filter_complex "[0:v]fps=10[rate], [rate]scale=1280:720, crop=in_w,
drawtext=fontfile=RobotoMono-Medium.ttf: text=\'test\': fontsize=50:
fontcolor=white: box=1: boxcolor=black at 0.5: boxborderw=5" -update 1

it works and returns:
Input #0, dshow, from 'video=Cam Link 4K':
  Duration: N/A, start: 136428.863000, bitrate: N/A
  Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1920x1080, 60
fps, 60 tbr, 10000k tbn
Stream mapping:
  Stream #0:0 (rawvideo) -> fps
  drawtext -> Stream #0:0 (png)
Press [q] to stop, [?] for help
Output #0, image2, to 'public\img.png':
    encoder         : Lavf59.3.101
  Stream #0:0: Video: png, rgb24(pc, progressive), 1280x720, q=2-31, 200
kb/s, 10 fps, 10 tbn
      encoder         : Lavc59.2.100 png

then sending:
   c crop -1 w=100
the retun is:
   Command reply for stream 0: ret:-40 res:
and nothing changes

instead trying:
  c drawtext -1 reinit fontcolor=red
the retun is:
  Command reply for stream 0: ret:0 res:
and the text turns red

what am i missing?

Bedste hilsner / Best regards

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