FFMPEG: using filters for adding transparent watermark

Question

how can i combine these two lines of code for adding transparent watermark (with Dynamic size)

ffmpeg -i 1.gif -i logo.png -filter_complex "[1]format=rgba,colorchannelmixer=aa=0.5[logo];[0][logo]overlay=(W-w)/2:H-h-5" -c:a copy output.gif

ffmpeg -i 1.gif -i logo.png -filter_complex "[1][0]scale2ref=w=oh*mdar:h=ih*0.1[logo][video];[video][logo]overlay=(W-w)/2:H-h-5" -c:a copy output.gif

i have tried the following code:

ffmpeg -i 1.gif -i logo.png -filter_complex "[1][0]scale2ref=w=oh*mdar:h=ih*0.1[logo][video];[1]format=rgba,colorchannelmixer=aa=0.5[logo];[0][logo]overlay=(W-w)/2:H-h-5" -c:a copy output.gif

i got the following Error: Filter scale2ref has an unconnected output

Answer 1

Outputs of every filter must be connected to something, and your [video] output pad of scale2ref is not, hence the error.

You need to feed [video] instead of [0] to the overlay filter:

You need to make sure all the filter input & output pads are connected. In your case, format and overlay need to use the output of scale2ref instead of reusing the input streams:

ffmpeg -i 1.gif -i logo.png \
  -filter_complex "[1][0]scale2ref=w=oh*mdar:h=ih*0.1[logo1][video];\
                   [logo1]format=rgba,colorchannelmixer=aa=0.5[logo];\
                   [video][logo]overlay=(W-w)/2:H-h-5" \
  -c:a copy output.gif

[Edit: fixed other labeling issues]