Premiere Pro uses metadata associated with clips to know how to play them back. This metadata is normally added correctly when the media is created (by the camera, for example), but occasionally it might be wrong. Sometimes, you’ll need to tell Premiere Pro how to interpret clips.
You can change the interpretation of clips for one file or multiple files in a single step. All selected clips are affected by changes you make to interpretation.
Choosing audio channels
Premiere Pro has advanced audio management features. You can create complex sound mixes and selectively target output audio channels with original clip audio. You can work with mono, stereo, 5.1, Ambisonics, and even 32-channel sequences and clips with precise control over the routing of audio channels.
If you’re just starting out, you’ll probably want to produce sequences mastered in stereo using mono or stereo source clips. In this case, the default settings are most likely what you need.
When recording audio with a professional camera, it’s common to have one microphone record onto one audio channel and a different microphone record onto another audio channel. These are the same audio channels that would be used for regular stereo audio, but they now contain completely separate sound.
Your camera adds metadata to the audio to tell Premiere Pro whether the sound is meant to be mono (separate audio channels) or stereo (channel 1 audio and channel 2 audio combined to produce the complete stereo mix).
You can tell Premiere Pro how to interpret audio channels when new media files are imported by choosing Premiere Pro > Preferences > Timeline > Default Audio Tracks (macOS) or Edit > Preferences > Timeline > Default Audio Tracks (Windows).
The Use File option means Premiere Pro will use the audio channel settings applied to the clip when it was created. You can override that option for each media type using the appropriate menu.
If the setting was wrong when you imported your clips, it’s easy to set a different way to interpret the audio channels in the Project panel.
Click the name of the Theft Unexpected bin to bring it to the front. If the bin is not open, double-click it to open it in the Project panel.
Right-click the Reveal clip in the Theft Unexpected bin and choose Modify > Audio Channels.
When the Preset menu is set to Use File, as it is here, Premiere Pro will use the file’s metadata to set the channel format for the audio.
In this case, Clip Channel Format is set to stereo, and Number of Audio Clips is set to 1—that’s the number of audio clips that will be added to a sequence if you edit this clip into it.
Now look at the channel matrix below those options. The Left and Right audio channels of the source clip (described as Media Source Channel) are both assigned to a single clip (described as Clip 1).
When you add this clip to a sequence, it will appear as one video clip and one audio clip, with both audio channels in the same audio clip.
Open the Preset menu, and choose Mono.
Premiere Pro switches the Clip Channel Format menu to Mono, so the Left and Right source channels are now linked to two separate clips.
This means that when you add the clip to a sequence, each audio channel will go on a separate track, as separate clips, allowing you to work on them independently.
It’s common for professional video to be recorded on a camera with relatively low-quality audio, while high-quality sound is recorded on a separate device. When working this way, you’ll want to combine the high-quality audio with the video by merging them in the Project panel.
The most important factor when merging video and audio files in this way is synchronization for the audio. You will either manually define a sync point—like a clapperboard mark—or allow Premiere Pro to sync your clips automatically based on their original timecode information or by matching up their audio.
If you choose to sync clips using audio, Premiere Pro will analyze both the in-camera audio and the separately captured sound and match them up. The option to sync automatically using the audio in both clips makes it worthwhile attaching a microphone to your camera, even if you know you won’t use the audio in post-production. The following steps are described for your information only–no need to follow along.
If you don’t have matching audio in the clips you are merging, you can manually add a marker to each clip you want to merge on a clear sync point like a clapperboard. The keyboard shortcut to add a marker is M.
Select the camera clip and the separate audio clip, right-click either item, and choose Merge Clips.
Under Synchronize Point, choose your sync method, and click OK.
There’s an option to use audio timecode (sometimes useful for older archived tape-based media).
There’s also an option to automatically remove the unwanted audio included with the audio-video clip. You may want to keep that audio, though, just in case there’s an issue with the external microphone audio.
A new clip is created that combines the video and the “good” audio in a single item.
Interpreting video footage
For Premiere Pro to play a clip correctly, it needs to know the frame rate for the video, the pixel aspect ratio (the shape of the pixels), and, if your clip is interlaced, the order in which to display the fields. Premiere Pro can usually find out this information from the file’s metadata, but you can change the interpretation easily.
Use the Media Browser panel to import RED Video.R3D from the Assets/Video and Audio Files/RED folder. Double-click the clip to open it in the Source Monitor. It’s full anamorphic widescreen, which is wider than regular 16×9 footage. This wider aspect ratio is achieved by using pixels that are not wider.
Right-click the clip in the Project panel and choose Modify > Interpret Footage.
The option to modify audio channels is unavailable because this clip has no audio.
Right now, the clip is set to use the pixel aspect ratio setting from the file: Anamorphic 2:1. This means the pixels are twice as wide as they are tall.
In the Pixel Aspect Ratio section, select Conform To, choose Square Pixels (1.0), and click OK. Take a look at the clip in the Source monitor.
The clip looks almost square!
Try another aspect ratio. Right-click the clip in the Project panel and choose Modify > Interpret Footage. Choose DVCPRO HD (1.5) from the adjacent menu. Then click OK, and take a look at the clip again in the Source monitor.
From now on, Premiere Pro will interpret the clip as having pixels that are 1.5 times wider than they are tall. This reshapes the picture to make it standard 16:9 widescreen.