Problem with volume keyframing in PD17

Harmen

Newbie Joined: Nov 01, 2018 15:29 Messages: 37 Offline

Solved by

Dec 09, 2018 11:08

I am having trouble adjusting the volume of a key frame in a audio clip. The volume is currently set at -28 and I am trying to set it to -26 but it keeps reverting to -28. When I set it at -24 it sets itself to -21.9! See video https://youtu.be/i5T2LQWCXj4. I'm baffled.

I think you can try this for yourself. Take the sample Skateboard.mp4 and try to put the volume somewhere at the track at -26dB. It might look as if the program is accepting that but jump 1 frame back and forth and you will see that it adjusted the volume to -28dB.

I have addessed this to support but the response has been...disappointing ("1. Check the minimum system requirements. 2. Update graphics card driver to the latest." etc. ; "May we know the exact action that you perform when adjusting the volume Keyframe Settings."; "Please be informed that there is an alternative way to use volume keyframes to mix an individual clip's audio in the timeline, Kindly hold down the Ctrl key on your keyboard and then click on the audio level line at the point where you want to change the audio level. Drag the volume keyframe up to increase the volume, or down to decrease the volume.") They don't seem willing to really check my problem, they don't try to reproduce the problem that I am having and come up with suggestions that are not in any way thought through.

I want to set the volume of a key frame at a value of for instance -24dB. But the program rounds it off at -21.9dB. The same with -26dB (goes to -28dB). Is it supposed to behave that way or not?

JL_JL

Senior Contributor Location: Arizona, USA Joined: Oct 01, 2006 20:01 Messages: 6091 Offline

Dec 10, 2018 10:59

Quote I want to set the volume of a key frame at a value of for instance -24dB. But the program rounds it off at -21.9dB. The same with -26dB (goes to -28dB). Is it supposed to behave that way or not?

Yes, I believe that is correct for how CL handled the change from the older amplitude adjustment to the dB adjustment. For a little history, see this old thread: https://forum.cyberlink.com/forum/posts/list/30556.page#post_box_167687

So basically I don't think CL really incorporated a true input of dB, but map the dB slider position or numeric input to the older linear amplitude scale which had integer adjustments from 1-100. Since a log scale relationship between dB and amplitude, one loses resolution in the -dB adjustment area. This can be seen in the attached graph with the overall and expanded correlation between dB and the linear 100 points of amplitude adjustment. So, if one tries to enter a value like your -24dB, the only linear options were an adjustment of 1 or 2, so you get the -21.9dB. Try to enter -20dB, you get -18.4dB for the same reason, the dB level needs to map to a linear amplitude adjustment of 2 or 3, so you get 3 or -18.4dB.

The same thing occurs in the higher positive dB area too, it's just not as obvious because of the log scale and the 100 linear point spacing. Try to enter 8.5dB for instance, you get 8.6dB, subtle, but because of the same reason.

Jeff


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Harmen

Newbie Joined: Nov 01, 2018 15:29 Messages: 37 Offline

Dec 10, 2018 11:27

Quote

Yes, I believe that is correct for how CL handled the change from the older amplitude adjustment to the dB adjustment. For a little history, see this old thread: https://forum.cyberlink.com/forum/posts/list/30556.page#post_box_167687 etc

Thanks Jeff, that makes sense. It does not solve my problem but at least it explains the behavior of the program. I'd rather see a more refined way of entering the volume though. I have a track with narration and I want to add music in the backgrount to it. With -21.9dB I find the music just a little too loud and with -28dB too soft. Maybe my ears are too sensitive but the result in PD is not what I hoped for.

JL_JL

Senior Contributor Location: Arizona, USA Joined: Oct 01, 2006 20:01 Messages: 6091 Offline

Dec 10, 2018 11:50

Quote Thanks Jeff, that makes sense. It does not solve my problem but at least it explains the behavior of the program. I'd rather see a more refined way of entering the volume though. I have a track with narration and I want to add music in the backgrount to it. With -21.9dB I find the music just a little too loud and with -28dB too soft. Maybe my ears are too sensitive but the result in PD is not what I hoped for.

Use a free audio editor like Audacity or just do a music render in PD with a partial volume adjustment and then use that produced audio clip in your PD project and adjust the volume again. This PD approach moves you away from the course linear amplitude dB region to something more dense.

Jeff