4 Replies Latest reply on Jan 10, 2017 11:18 PM by Rick Gerard

    Convert Audio to Keyframes Not Accurate

    GlitchMaster

      Hello, I'm a music producer and I'm trying to sync parts of my visualizer to parts my song, specifically the drums. So I exported the kick and snare track and converted that to keyframes, expecting the keyframes to spike at the transients. However, in the space between the drums the keyframes hover around 30% even though there is complete silence at that point in the audio file. The transients also only peak at around 50%, even though they reach 0dbfs in the audio file. Why is this and is there a way to fix it?

       

      -GlitchMaster

        • 1. Re: Convert Audio to Keyframes Not Accurate
          Mylenium Most Valuable Participant

          You have a wrong understanding how this works. This simply converts the overall amplitude within the frequency range, not specific "hits" or whatever. Unless your hits are exactly one sample long at a maximum amplitude of 100% and also happen to be exactly at the correct time position, they will never max out. The rest doesn't really matter. One would simply remap/ multiply or whatever the values in the expression that actually uses them. This is a common workflow.

           

          Mylenium

          • 2. Re: Convert Audio to Keyframes Not Accurate
            GlitchMaster Level 1

            Yeah, I just have the kick and snare in an audio file, they are the "hits" that I want to transfer into keyframes, they do peak at 100% (0dbfs) and have a fast decay (not 1 sample though). Here's what the audio clip looks like in FL Studio:

            https://gyazo.com/c4b22cb7f64ac2344bcef0f935892cf9

             

            As you can see, there are the hits at the exact right times that I need them and silence in between. However, in After Effects this silence gets turned into a percentage value from around 10-30%, with the hits not peaking, even though they are as loud as they can possibly be in a 24-bit audio file.

             

            -GlitchMaster

            • 3. Re: Convert Audio to Keyframes Not Accurate
              GlitchMaster Level 1

              Wait! I figured it out, converting the audio to keyframes converted all the audio in the composition into keyframes, not just the trigger. All I had to do was mute the song then convert the trigger!

               

              -GlitchMaster

              • 4. Re: Convert Audio to Keyframes Not Accurate
                Rick Gerard Adobe Community Professional & MVP

                You should look into expressions. That's the effective way to use Audio to Keyframes.

                 

                In CC 2017 you should see values for Both channels of about 11 or 12 for zero DB if you look at the graph editor.

                Screen Shot 2017-01-10 at 11.09.48 PM.png

                I'm not sure what you are driving or where you are getting 50% but here's how you write an expression that takes everything from 49.9 and below to zero and everything from 59 and above to 100 that you could apply to the scale of a layer. Just using the audio to keyframe values will not produce a quick on and off. This expression basically sets everything below 49.9 to zero and everything from 50 and above to one hundred.

                t = thisComp.layer("Audio Amplitude").effect("Both Channels")("Slider");

                s = linear(t, 49.9, 50, 0, 100);

                [s, s]

                With this particular clip I decided that 4.62 was my switch point buy looking at the graph editor.

                Screen Shot 2017-01-10 at 11.15.22 PM.png

                So the expression to switch an audio layer on and off every time that the audio crossed above 4.62 that the layer would scale to 100%. I set the upper value to 6 to give the scale a little motion.

                t = thisComp.layer("Audio Amplitude").effect("Both Channels")("Slider");

                s = linear(t, 4.62, 6, 0, 100);

                [s, s]