Chapter 8: Freezing and Rendering
8.1 Freezing
If you find that your edits require more processing power than your computer can provide, and upgrading is not an option, freezing may just be the answer to your needs.
The freeze function works to free up CPU usage by bouncing frozen tracks into a single audio file.
To “freeze” a track:
- Click the track name to display its properties.
- Click the “freeze track” button in the properties-panel.
“Freezing” causes Tracktion to render the selected track(s), along with their filters, down to a single temporary file on your hard-drive. A progress bar will be shown whilst the tracks are being frozen. After a few moments, the freeze operation will complete. The frozen tracks will be shown with their height at the smallest size. Any filters used by the tracks will be disabled (Fig. 8.1.1).
By combining all frozen tracks into one single file, Tracktion makes it possible to play as many tracks as you need. Even laptop computers, usually hindered by slower hard-drives than their desktop counterparts, will be able to handle the demands of large projects, making work on the road a real possibility.
There is a cost to this seemingly unlimited power though. Freezing and unfreezing tracks can take a long while, as the time taken to freeze or unfreeze will grow longer with every extra frozen track. It is also not possible to make any changes to a frozen track. Whether it be editing MIDI, audio, or changing the volume or pan settings, if you need to change some aspect of a track you will need to unfreeze it. Unfreezing tracks is simply a case of displaying the track properties as normal and clicking the “unfreeze” button. Once unfrozen, your tracks will return to normal size, with all filters and settings just as you left them.
Freeze can be very useful when making audio recordings in edits that already have lots of audio tracks. With these audio tracks already placing a high load on your hard-drive, recording takes may be spoilt by drop-outs. Freezing the existing audio tracks will help to ensure that hard-drive performance issues do not impact on recording quality.
When mixing projects that rely on freeze, you may be able to reduce time spent waiting for tracks to freeze and unfreeze by working on the mix in sections. For example, perhaps you can get away with freezing only the bass and percussion, leaving you free to mix the vocals and lead instruments. When you are ready to move on, you could simply unfreeze the edit, and freeze everything that will not be altered during the next mixing section.
If you find that you need to tweak levels and effects constantly on some tracks, you may want to consider using track rendering instead.
8.2 Rendering
Rendering is not quite as easy to use as track freezing, but it does have a few advantages.
Unlike with freeze, in which all tracks are stored in a single file, render creates a new file for each rendered track. The rendered audio file will take the resolution and sample rate of the default audio output device.
To render a track:
- Click the track name to display its properties.
- Click the “render track” button in the properties-panel.
- You will be prompted for a location to store the rendered file. Typically, you would use the project’s local folder.
- Once you have told Tracktion where to store the file, you will see a dialogue-box like the one shown in Figure 8.2.1.
This dialogue-box controls what happens to the source track after the render operation is complete.
Replace: This option removes the source track, and places the rendered audio clip in its place. This operation is destructive. A rendered track cannot be un-rendered at a later stage.
Add rendered tracks: This option inserts a new track, containing the rendered clip, into the edit. The source track is not affected. Whilst not as elegant as freeze, this option provides a way to render tracks non-destructively.
Cancel: This option simply aborts the render.
A point worth noting here is that after rendering, your track will take the form of a standard audio clip. This means it can be processed, edited, and passed through whatever filters you want, just like any other audio clip.
Rendering tracks containing audio clips will not reduce the load on your computer unless they also contain filters that are processor intensive.
Muting a track has the effect of reducing any processor load it may otherwise have generated. You can make use of this when using the “add rendered tracks.” When the new track has been created, the source track can be muted and moved to the bottom of the track-list out of the way. If at any time, you do need to make changes to the original, just reactivate the track, edit it, and re-render it.
Tip: Filters that are disabled will not be rendered. If, for example, you wished to render a track without making the current compression and volume settings permanent, you could disable these filters before rendering. Use the “replace” render option, and drag the disabled filters to the new track. There you can re-enable them and edit them at a later stage.
