volume filter and fades with level property

[EZWrighter]

Trying to use the volume filters newer "level" property to set volumes since gain has been deprecated. Is there an appropriate way to use it for fades like "gain" and "end" properties were used?

Specifically, I have a background audio track I use the the volume filter on to reduce the levels by -30db which works great. But I also want to fade the last X seconds to silence at the end. Previously I just would have set a second filter for the last X frames and used the gain and end to shove it down to -70db.

Really appreciate any help or guidance.

[bmatherly]

You can use a single filter and use property animation on the "level" property to keyframe the property value.
https://mltframework.org/docs//propertyanimation/

[EZWrighter]

Thanks Brian! Appreciate your insight. This was my leveling melt example and it seemed to work like I expected: melt video.mp4 -audio-track backgroundMusic.mp3 -filter volume level="0|=-3:00~=-30;-1~=-90" -transition mix -consumer avformat:output.mp4 acodec=aac vcodec=libx264 crf=18 threads=8 movflags=+faststart

This added an audio track at -30dB until the last 3 seconds then faded out the background audio to -90dB until the last frame. Hopefully this example will help others with the syntax as none of the command line animation quoted string details is described in the doc. Couldn't find any examples online either. Anyway, cheers and thanks again.

[ddennedy]

If you look at the XML Shotcut or Kdenlive generates, you can find plenty of examples. Also, AI is sometimes better now than a general web search with lots of noisy results.