Mixing clip types in a sequence

You can mix clips with different frame rates, frame aspect ratios, and frame sizes in the same sequence. For example, if you drop an HD clip into a sequence in an SD project, the clip will be letter-boxed and scaled to the SD frame size automatically. Similarly, if you drop an SD clip into a sequence in an HD project, the clip will be pillar-boxed automatically.

A render bar will appear above any clip in a Timeline panel with attributes not matching the sequence settings. The render bar indicates that those clips will have to be rendered before final output. However, it doesn't necessarily indicate these clips can't be previewed in real-time. If a yellow render bar appears above the clip, Adobe Premiere Pro can probably play it back in real time without rendering. If, however, a red render bar appears above the clip, Adobe Premiere Pro probably can not play it back without rendering.

A clip with a frame rate different from the frame rate of the sequence will play back from a sequence at the frame rate of the sequence.