About Real-Time Playback Options

The following options, most of which are available in both the RT pop-up menu and the Playback Control tab of the System Settings window, allow you to control the quality of real-time playback.

Safe RT

The Safe RT mode guarantees that effects are played back at the quality and frame rate you specify and that no frames are dropped during playback. If Final Cut Pro anticipates that your computer won’t be able to perform all the effects calculations in real time, the render status bar for that segment becomes red, which means you have to render before you can play back.

Figure. Timeline window showing red render bars that indicate that rendering is required.

Before using the Print to Video or Edit to Tape commands to output to tape, you can switch to Safe RT mode to see how many segments require rendering.

Important: Even though the Safe RT option guarantees that no frames will be dropped because of processor limitations, frames may still be dropped if your scratch disk cannot maintain the necessary data rate during playback. This can be a problem if you have multiple video streams playing from a relatively slow hard disk. In this case, the Timeline may show a green render bar, indicating that the processor can handle the effects load, but you may still drop frames because of slow disk performance. To solve this issue, you can limit the acceptable real-time data rate of media playback in the General tab of the User Preferences window. For more information, see Choosing Settings and Preferences.

Unlimited RT

Choosing this option tells Final Cut Pro to play as many frames as possible when your effects exceed the processing power of your computer. Final Cut Pro does this by spending time to process some frames in real time while skipping others completely. Unrestricted real-time playback allows you to play more effects but increases the likelihood that your sequence will drop frames during playback. This mode is useful for getting a real-time preview of complex effects compositions. Embedded Motion projects can also be played back in this mode.

Red render bars in Safe RT mode become orange in Unlimited RT mode, indicating that Final Cut Pro may drop frames during these segments to achieve real-time playback.

Figure. Timeline window showing orange status bars that indicate Unlimited RT playback.

Note: Segments that can play back without dropping frames still appear with colored render bars as they would in Safe RT mode.

Unlimited RT mode uses the playback video quality and frame rate options you choose in the RT pop-up menu or the Playback Control tab. However, this mode overrides the Play Base Layer Only option and attempts to calculate all applied effects. For more information, see Play Base Layer Only.

Unlimited RT performance varies greatly depending on the effects in your sequence, the codec and data rate of your media, and the processing power of your system. Some segments of your sequence may play back without dropping any frames, while other sections may rarely update the Canvas.

Tip: Turning on Unlimited RT is the only way to turn on third-party FXScript filters and transitions to play in real time, if they’re capable of doing so.

Play Base Layer Only

The Play Base Layer Only option takes a unique approach to playing back processor-intensive segments. With this option selected, any segment that requires rendering in Safe RT mode (in other words, any segment with a red render bar) is restricted to original media playback, and all effects, including compositing modes, are turned off.

Here are the playback rules for the Play Base Layer Only option:

  • Effects that can be played back in real time are played just as they would be in Safe RT mode.

  • If a clip has effects applied, the effects are ignored if they can’t be played in real time. Only the underlying clip media is displayed.

  • Clips with compositing modes applied can never play back in real time, so they are ignored and only clips on lower-numbered tracks are displayed. Of course, a clip on a lower-numbered track that has a compositing mode applied will also be ignored.

  • Transitions that cannot be played back in real time are disabled, so only the underlying clip media is displayed.

The Play Base Layer Only option also affects audio playback. When playing over an unrendered portion of a sequence, no effects are played back. The number of audio tracks that play depends on whether or not you have selected the Play Base Layer Only option.

  • If selected: The first two tracks of audio play back.
  • If unselected: The number of audio tracks that play back is determined by the number of real-time audio tracks you have set in the General tab of the User Preferences window.
    Figure. Timeline window showing clips that will play back without effects.

Beep When Playing Unrendered Audio

This option is available only in the Playback Control tab of the System Settings window. When this option is selected, audio clip items that require rendering are played back as audible beeps. This is the audio equivalent of the “Unrendered” screen you see when your video requires rendering. If the Play Base Layer Only option is not selected, the beeps are not heard. For more information, see Play Base Layer Only.

Scrub High Quality

When this option is selected, video displayed in the Canvas is shown at full quality when you scrub or when the video is stopped. If you deselect this option, the video quality during scrubbing is determined by the current Playback Video Quality setting (see Playback Video Quality). Deselecting this option allows you to improve responsiveness during scrubbing, especially when using processor-intensive codecs such as HDV, or options such as multiclip playback.

Playback Video Quality

Most codecs support more than one level of playback quality to improve real-time performance. Some codecs support three playback quality levels—high, medium, and low—while others support only high and low quality. Selecting a lower playback quality can increase the number of simultaneous real-time effects you can play.

  • Dynamic: This option allows Final Cut Pro to automatically change between high, medium, and low quality as necessary to maintain real-time playback. In this case, the quality of the video resolution can change frame by frame. For more information, see Multiclip Playback.
  • High: Guarantees full-frame, full-resolution video playback. Video interlacing is preserved.
  • Medium: Displays every other pixel and every other line (this is known as quarter frame resolution). Because only half the lines are shown, the video is displayed without interlacing. Media is decompressed using a full-quality decompression algorithm.
  • Low: Like the Medium quality option, displays video at quarter frame resolution. However, your media is decompressed and displayed with a low-quality decompression algorithm, which requires significantly less processing power.

Playback Frame Rate

The more you reduce the number of frames Final Cut Pro calculates each second, the more effects can be calculated in real time.

  • Dynamic: This option varies the displayed frame rate as necessary to achieve the highest-quality playback with the most effects. When more processing power is required, Final Cut Pro can reduce the frame rate to spend more time calculating fewer frames. When few or no effects are applied, Final Cut Pro can return to playback at the full frame rate. For more information, see Multiclip Playback.
  • Full: Your sequence plays back at the frame rate (editing timebase) assigned in the Sequence Settings window.
  • Half: Your sequence plays back at half its assigned frame rate. For example, if the frame rate of your sequence is 24 fps, the playback frame rate is 12 fps.
  • Quarter: Your sequence plays back at a quarter of its assigned frame rate. If the frame rate of your sequence is 24 fps, the playback frame rate is 6 fps.

About Dynamic Real-Time Playback

To maximize the number of effects you can see during real-time playback, you can choose to have Final Cut Pro automatically adjust the video quality, the frame rate, or both during playback. This is called dynamic real-time playback.

Dynamic real-time playback continually adjusts video quality on a frame-by-frame basis. Segments of a sequence that require minimal processor workload are displayed at higher quality, and more processor-intensive segments are displayed at lower quality. Since Final Cut Pro automatically adjusts the playback quality as necessary, you always get the highest-quality playback possible without having to stop playback to make video quality adjustments.

Playback video quality and frame rate are independent settings, so you can choose to make one dynamic while keeping the other fixed. For example, if you need to see every frame during playback, you should set the playback frame rate to Full while setting the playback video quality to Dynamic. In this case, your sequence video quality may be reduced during playback, but you will always see every frame. On the other hand, if you are doing detailed compositing work that depends on high-quality video display, you can set your sequence playback video quality to High and set your sequence frame rate to Dynamic.

If neither frame rate nor video quality is critical, you can choose Dynamic for both playback video quality and frame rate.

Multiclip Playback

This option allows you to watch all angles of multiclip play at once in the Viewer while you switch or cut in real time. When this option is selected and you choose Open from the Playhead Sync pop-up menu, multiclips in your sequence are automatically opened in the Viewer, and all angles play back at the same time while the active angle plays in the Canvas. For more information, see Working with Multiclips.

Pull-down Pattern

If your sequence has a frame rate (editing timebase) of 23.98 or 24 fps and you want to output to an NTSC or PAL device via FireWire, you can choose one of five pull-down insertion patterns. Pull-down insertion is a method of converting film or other progressively scanned material to an interlaced format playing at a different frame rate. For detailed information about pull-down patterns, see Working with 24p Video.

The Pull-down Pattern pop-up menu is available in the Playback Control tab of the System Settings window. Pull-down options appear in the RT pop-up menu only when your sequence has a frame rate of 23.98 or 24 fps and Final Cut Pro is currently set up to output to a DV NTSC or PAL FireWire device. Some options may not be available if your computer does not have sufficient processing power.

The following three pull-down patterns are available when your sequence has a frame rate of 23.98 fps and you choose 29.97 fps external video output.

  • 2:3:2:3: This pattern is the most processor-intensive method of introducing pull-down but outputs NTSC video with the least noticeable temporal artifacts. For this reason, 2:3:2:3 pull-down is generally considered to have the most acceptable quality of motion. This pull-down pattern is also referred to as 3:2 pull-down.
  • 2:3:3:2: Also known as advanced pull-down. This pattern requires less processing to output than 2:3:2:3 pull-down because 2:3:3:2 pull-down requires recompression or regeneration of fewer frames, but the perceived motion quality is lower than when using 2:3:2:3 pull-down.
  • 2:2:2:4: This pull-down pattern requires less processing, so it is a good choice if you want to preview video with as many real-time effects as possible. Keep in mind that if you choose this pull-down pattern, you won’t be able to easily remove the pull-down later.

The following two patterns are available when your sequence has a frame rate of 24 fps and you choose a 25 fps external video output.

  • 24@25 Pull-down: In this pattern, frames 12 and 24 are pulled down for a duration of three fields instead of two, creating a subtle stutter each half second. For 25 fps output, this pattern has the best perceived motion quality.
  • 24@25 Repeat: This pattern simply repeats every 24th frame once to fit 24 fps footage into 25 fps. This causes a noticeable stutter every second, but requires less processing than the 24@25 pull-down pattern because no special interlacing is required.

Gamma Correction

This pop-up menu is available only in the Playback Control tab (not the RT pop-up menu) on older systems with graphics cards that don’t support gamma correction. If your computer’s graphics card does not support gamma correction, you have two options:

  • Accurate: High-quality gamma correction. This option is the most accurate but also requires the most processing power.
  • Approximate: Lower-quality gamma correction. This option leaves more processing power available for real-time effects but results in less-accurate color and brightness rendition.

For more information, see Choosing Real-Time Playback Gamma Correction Options.

Record Settings

When using the Print to Video and Edit to Tape commands, you can control the quality of video being output to tape independently of the real-time playback video quality in the Canvas and Timeline.

Full Quality

When this option is selected, video is always output to tape at the highest quality. Areas of your sequence that won’t play back at full resolution in real time must be rendered prior to output.

Use Playback Settings

Final Cut Pro uses the selected real-time effects playback settings when outputting your sequence to tape. If, as a result, your sequence will output at less than full quality, you are warned of this prior to output. Outputting to tape at draft quality is useful for quickly creating sample tapes of your program when you don’t have the time to render all necessary effects first.

Video Scopes Playback

When the Video Scopes tab of the Tool Bench window is open, you can choose whether the scopes update in real time or only when playback is stopped.