HitFilm's editor can have multiple audio tracks. This makes it possible to build up a soundscape of multiple audio clips, including dialogue, sound effects, music etc. For information on using tracks see Audio and video tracks.
A range of features are included to aid with editing your audio.
The audio meters panel shows your audio levels, so that you can adjust audio levels appropriately, ensuring your soundtrack is able to be heard while avoiding clipping.
Audio clipping, or peaking, is when the audio output is beyond the range of playback. This results in a distorted result which is best avoided.
Audio peaks are drawn as green bars during playback or when moving the playhead. Each audio channel is displayed as a separate bar. Thin white lines are drawn separately indicating the peak volumes of each channel and the peak volume is displayed above the bars. These peak values are held momentarily so that you can easily identify unwanted clipping.
If clipping occurs, the peak volume readout turns red on the affected channel. This is a useful way to identify areas where the audio mix is too loud and may cause distortion on playback. Reducing the combined volume of the audio tracks in that area will avoid clipping.
Clipped peaks will remain red until you start a new playback or move the playhead.
The peak meter is not directly equivalent to loudness or volume. Instead it represents the amplitude level. This will often correlate with loudness but other factors (such as frequency) can also have an effect on perceived loudness.
Understanding the meter scale
The meter scale is dBFS (decibel full scale), which means that 0dBFS is the maximum possible audio level before clipping occurs.
The scale extends to +6, which gives you an indication of how far past 0dBFS audio is peaking, so that you can make appropriate adjustments to avoid clipping.
Peak bars are drawn in green when at a safe level (considered below -9dBFS). The color gradient shifts from green to yellow to red, with red marking 0dBFS.
Static vs dynamic peaks
The audio meter's menu has an option to hold peaks. This prevents the peak indicators from ever lowering during playback, known as static peaks. Therefore by the end of playback you will have a definite readout for the maximum peak level during that section of the timeline, without needing to observe the audio meters for the duration of playback.
With the hold peaks option turned off the audio meters use dynamic peaks, which update every two seconds. After two seconds the bars will fall back down if the peaks have been lower than an earlier peak.
The timeline and Trimmer display waveforms for audio. This provides a visual representation of the audio over time, making it easier to position clips based on audio content.
The Options screen lets you choose between several waveform types.
|•||Channel list: Displays individual waveforms for each channel in the audio stream and is a common representation of audio. So you'll see one waveform for mono audio, 2 waveforms for stereo, and 6 waveforms for 5.1 surround sound. It can be useful in order to see where a particular channel has silence, for example.|
|•||Channel composite: This simply draws all waveforms from the audio stream over the top of each other. So you only ever see one waveform even if the source has stereo or 5.1. This view isn't particularly useful for detailed work but can be helpful if there is limited screen space and you still want to see a waveform plotted.|
|•||RMS amplitude: Similar to Channel Composite, this displays a single graph of all channels in the audio stream, but instead of plotting a waveform it shows the average levels of the audio signal over time. Viewing an average of audio levels in this way is a better method to determine its volume than inspecting a waveform because it is a better approximation of how our ears and brains perceive loudness.|
Note that RMS amplitude is still only a loose correlation or rough guide. There are many factors which affect human perception of loudness which are not included in an RMS graph, such as the frequency of sounds. (Our ears are more or less sensitive to different frequencies, meaning that the same power does not always result in the same perceived loudness.)
A clip's volume can be changed over time. By adjusting the volume of multiple clips you can build up a more interesting soundtrack.
Volume can be adjusted in the Controls panel or directly on the timeline. Every audio clip has a volume bar which can be dragged up and down.
By default the volume bar will change the volume of the entire clip. You can add keyframes by holding Ctrl and clicking on the volume bar.
Keyframing can also be turned on and off in the controls panel by clicking the keyframe button to the left of the Volume property.
With the audio property selected in the Controls panel you can jump between keyframes using the keyframe navigation buttons at the top of the timeline.
HitFilm includes several effects to further adjust your audio. These are found in the Effects library in the Audio folder.
To add an audio effect to an audio clip drag it from the Effects panel onto the clip. You can then customize the effect in the Controls panel.
For information on individual audio effects, see the Audio effects chapter.