Audio envelope creates clipped pop

My first day with HitFilm, so apologies if I've missed something obvious.

I added a volume envelope to silence a selection of audio. When the audio comes back in, it creates a huge spike that pops and clips into the +12db red.

Here you can see an audio track. At the point of the red arrow, the audio creates a huge pop.

Here is the meter at that point...

  • You can replicate this with any audio file.
  • The spike is rendering into the export also.
  • It does not happen with a gradual slope (>3 seconds), but that is not useful for quick silences (e.g. silencing coughs). 

Any advice would be appreciated!

If there is an alternative method of silencing a section of an audio track, that would be very useful to know too.




  • Anyone?

    Does this bahaviour not happen for anyone else?

  • NormanPCN
    NormanPCN Posts: 4,081 Enthusiast
    edited November 2016

    I just tried a test and I do hear a pop. At a one frame duration from min to normal the pop is massive. At two frames the pop is very slight. At three frames the pop is gone.

    You do need a certain about of time to go from min/mute to normal. I don't know if Hitfilms implementation requires more duration (to not pop) than robust audio control other apps might have. i.e. Audio editors or Vegas.

    I'm not sure what other to say but I would suggest you contact support to see what they think.

  • Triem23
    Triem23 Posts: 20,069 Ambassador

    An issue here is that cutting a waveform anywhere other than a "zero crossing" will cause pops. I don't think Hitfilm allows one to cut at a duration of less than one frame (unlike, say, Vegas, where audio edits can happen at the sample level), so this is hard to avoid any other way than using a fade. Although three frames @NormanPCN? I would have thought one would do it. 

    It might be better to trim audio in another program. Audacity is pretty good, and free. 

    The only in-Hitfilm alternative that comes to mind is to unlink the audio from the video and actually clip out the section of audio you want to remove. I haven't tried this (not currently on my PC), but, maybe that would eliminate pops? 

  • NormanPCN
    NormanPCN Posts: 4,081 Enthusiast
    edited November 2016

    I just tried the clip I tested in Vegas and it does not pop. The Vegas generated transition from -inf to 0dB was less than a frame. 24 fps timeline so a frame is about 41 milliseconds. 

    I used the Vegas ducking feature to generate the four points. For those who don't know, just define a selection (think in/out loop region in Hitfilm terms) and then drag the audio volume envelope/bar down. Vegas auto creates four frames with auto transition duration. Also, it should be noted that Vegas defaults to "smooth" keyframe interpolation on these volume envelopes. Hitfilm NLE keyframes are always linear AFAIK.

    For reference the video clip I used to test is from the Portal Combat Rough Assembly project. The audio is very low in those clips so pops are massively apparent. Kinda the opposite from my media clips (GoPro+mountain bike) and why I used that for testing. Also, anyone can test with the same media as me with publically available media.

    For reference the Vegas quickfade preferences is 10ms. This is automatically done when slicing audio events and such. As @Triem23 stated cuts on something other than a zero crossing can pop. Hence the quickfade. I am not sure if the quickfade duration applies to the ducking transition or if that value is some other duration. Either way Vegas knows what needs doing, when, and how to do it.

  • jnnn58
    jnnn58 Posts: 5
    edited November 2016

    Thanks for the input, @NormanPCN and @Triem23 - I appreciate you confirming the behaviour at your end!

    At least I know it's not a mistake in my workflow.

    @NormanPCN ... I think you hit the nail on the head with this:

    "Either way Vegas [or any other tool I've used] knows what needs doing, when, and how to do it"

    Technical limitations aside, this is disappointing :( I've just migrated from a mishmash of Vegas, Audacity, Camtasia (each tool can silence audio with no trouble) and I was really hoping to consolidate the workflow into HitFilm.

    It's strange that the inability to silence sections of audio without clipping seems like such a small complaint on its own - but it forces me to fall back on other traditional tools. As such, there's no real point committing myself to migrating to Hitfilm.

    I'll send a link to this thread to Hitfilm support so they're aware of the bug.

  • Triem23
    Triem23 Posts: 20,069 Ambassador

    Which version of Vegas are you on? Vegas and Hitfilm really work very well together, even without the integration. I actually use Hitfilm to do all my VFX and Compositing, and often a rough edit, but Vegas is my finishing editor. And with Hitfilm Ignite, Vegas has most of the Hitfilm effects, which is quite nice, since I know the effects will match across the two programs. Best of both worlds: Hitfilm's  VFX and animation to create the FX sequences and Vegas for buttery smooth assembly. Besides, Vegas really does the best audio editing tools of any NLE, period.

    Hitfilm is trying to be the all-in-one, and it's getting closer every revision. Right now it really is the ultimate swiss army knife of video.

    Yeah, there's an audio pop bug, but the Audio Mixer is new for HFP 2017... The hard part is done--getting a whole new interface coded and running. I wouldn't be surprised if they get it fixed pretty soon. Once that happens, you can consider migrating.

  • Thanks @Triem23, that's a very reassuring reply. I do like Vegas but it's never been the most stable tool 

    I was on a very old version of Vegas, but I'll probably spring for the newer Studio Platinum version. I can't really afford the pro version.

    I'll definitely stay updated on HitFilm development. I'm not loyal to any program so if it meets my needs and is more stable than Vegas, I'll jump ship!

  • CedricBonnier
    CedricBonnier Posts: 1,197 Staff

    @jnnn58 thanks for reporting this. I only briefly looked at it and unfortunately it doesn't seem to be an easy fix but we'll look at it in the future.

    Having a description of what other software do and how it's helping your workflow (and how it's better than HF) is important to us so thanks also to @NormanPCN and @Triem23, as always you guys are on point :)

  • CedricBonnier - I'm happy it's on your radar. 

    Is there an change log I can stay updated on so I know when I'm able to migrate to HF?

This discussion has been closed.