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Compression and data-rate basics

  1. Adobe Premiere Elements User Guide
  2. Introduction to Adobe Premiere Elements
    1. What's new in Premiere Elements
    2. System requirements | Adobe Premiere Elements
    3. Workspace basics
    4. Guided mode
    5. Use pan and zoom to create video-like effect
    6. GPU accelerated rendering
  3. Workspace and workflow
    1. Get to know the Home screen
    2. View and share auto-created collages, slideshows, and more
    3. Workspace basics
    4. Preferences
    5. Tools
    6. Keyboard shortcuts
    7. Audio View
    8. Undoing changes
    9. Customizing shortcuts
    10. Working with scratch disks
  4. Working with projects
    1. Creating a project
    2. Adjust project settings and presets
    3. Save and back up projects
    4. Previewing movies
    5. Creating video collage
    6. Create a video story
    7. Creating Instant Movies
    8. Viewing clip properties
    9. Viewing a project's files
    10. Archiving projects
    11. GPU accelerated rendering
  5. Importing and adding media
    1. Add media
    2. Guidelines for adding files
    3. Set duration for imported still images
    4. 5.1 audio import
    5. Working with offline files
    6. Sharing files between Adobe Premiere Elements and Adobe Photoshop Elements
    7. Creating specialty clips
    8. Work with aspect ratios and field options
  6. Arranging clips
    1. Arrange clips in the Expert view timeline
    2. Group, link, and disable clips
    3. Arranging clips in the Quick view timeline
    4. Working with clip and timeline markers
  7. Editing clips
    1. Reduce noise
    2. Select object
    3. Candid Moments
    4. Smart Trim
    5. Change clip speed and duration
    6. Split clips
    7. Freeze and hold frames
    8. Adjusting Brightness, Contrast, and Color - Guided Edit
    9. Stabilize video footage with Shake Stabilizer
    10. Replace footage
    11. Working with source clips
    12. Trimming Unwanted Frames - Guided Edit
    13. Trim clips
    14. Editing frames with Auto Smart Tone
  8. Applying transitions
    1. Applying transitions to clips
    2. Transition basics
    3. Adjusting transitions
    4. Adding Transitions between video clips - Guided Edit
    5. Create special transitions
    6. Create a Luma Fade Transition effect - Guided Edit
  9. Special effects basics
    1. Effects reference
    2. Applying and removing effects
    3. Create a black and white video with a color pop - Guided Edit
    4. Time remapping - Guided edit
    5. Effects basics
    6. Working with effect presets
    7. Finding and organizing effects
    8. Editing frames with Auto Smart Tone
    9. Fill Frame - Guided edit
    10. Create a time-lapse - Guided edit
    11. Best practices to create a time-lapse video
  10. Applying special effects
    1. Use pan and zoom to create video-like effect
    2. Transparency and superimposing
    3. Reposition, scale, or rotate clips with the Motion effect
    4. Apply an Effects Mask to your video
    5. Adjust temperature and tint
    6. Create a Glass Pane effect - Guided Edit
    7. Create a picture-in-picture overlay
    8. Applying effects using Adjustment layers
    9. Adding Title to your movie
    10. Removing haze
    11. Creating a Picture in Picture - Guided Edit
    12. Create a Vignetting effect
    13. Add a Split Tone Effect
    14. Add FilmLooks effects
    15. Add an HSL Tuner effect
    16. Fill Frame - Guided edit
    17. Create a time-lapse - Guided edit
    18. Animated Sky - Guided edit
    19. Select object
    20. Animated Mattes - Guided Edit
    21. Double exposure- Guided Edit
  11. Special audio effects
    1. Mix audio and adjust volume with Adobe Premiere Elements
    2. Adding sound effects to a video
    3. Adding music to video clips
    4. Create narrations
    5. Using soundtracks
    6. Music Remix
    7. Adding Narration to your movie - Guided Edit
    8. Adding Scores to your movie - Guided edit
  12. Movie titles
    1. Creating titles
    2. Adding shapes and images to titles
    3. Adding color and shadows to titles
    4. Editing and formatting text
    5. Motion Titles
    6. Exporting and importing titles
    7. Arranging objects in titles
    8. Designing titles for TV
    9. Applying styles to text and graphics
    10. Adding a video in the title
  13. Disc menus
    1. Creating disc menus
    2. Working with menu markers
    3. Types of discs and menu options
    4. Previewing menus
  14. Sharing and exporting your movies
    1. Export and share your videos
    2. Sharing for PC playback
    3. Compression and data-rate basics
    4. Common settings for sharing

About compression

When exporting a movie, you choose a codec to compress the information for storage and transfer (such as on a DVD), and to decompress the information so it can be viewed again. The name “codec” comes from an abbreviation of its function of compression and decompression. During compression, repetitive and unnecessary information in the original file is discarded, causing the original file to lose information. For this reason, most codecs are considered lossy. Some codecs, though lossy, still allow the file to retain a high level of quality. The DV and MPEG codecs are especially good at maintaining excellent quality. Compressing video reduces its file size and data transfer rate, facilitating smooth playback and reducing storage requirements. A variety of codecs are available; no single codec is the best for all situations. For example, the best codec for compressing cartoon animation is generally not effective for compressing live‑action video. When you export from Premiere Elements, you generally only need to choose your medium of delivery and the application will select the optimal codec for you.

If you intend for your exported movie to be played back from a hard disk or CD, make sure that the codec you use to export your video is available to the audience for your movie. Most codecs for digital video and the web are already available on a majority of systems. However, if you are using a codec that’s native to a particular product, make sure that your target audience uses the same product, or can easily obtain the codec that you used.

If you intend to create a DVD or record to tape, codec compatibility is irrelevant. Your audience only needs to have the hardware necessary to play back the file.

About data rate

With some video codecs, you can specify the data rate, which controls the amount of video information that is processed each second during playback. Specifying a data rate in Premiere Elements sets the maximum data rate because the actual data rate varies according to the visual content of each frame.

The data rate you specify depends on the purpose of the video. The following list describes data rate guidelines for some uses:

DVD production

The data rate should maximize quality while fitting the entire program within the space available on the DVD. By default, Premiere Elements automatically adjusts the DVD data rate.

Non-DV videotape production

The data rate should be well within the data transfer rate of your hard disk because the video will be played back from the hard disk to the recording device. Check your documentation for information on the data transfer rate of your hard disk.

Hard disk playback

Determine the typical data transfer rate of your audience’s hard disks and set the data rate accordingly. Generally, 7200 rpm hard disks have sustained data rates of 20 to 35 MB per second, which is high. In comparison, the average data rate of digital video is 3.6 MB per second. So, to achieve high-quality playback, you may not need to set the data rate as high as 20 to 35 MB per second. However, if you are exporting video for use in another editing system or in a compositing application, such as Adobe After Effects, export at the maximum quality. Use a lossless codec, which is one that compresses without discarding information, and specify the data rate that the editing system supports for video capture and editing.

CD-ROM playback

The data rate depends on the speed of the CD drive. For example, if you are preparing a final video file for a double‑speed CD‑ROM drive (300 kilobytes per second) you might specify between 150 kilobytes and 200 kilobytes per second to account for both the data rate of the drive and the system overhead required to move the data.

Intranet playback

The data rate can be 100 kilobytes per second or faster, depending on the speed of your intranet. An intranet is an in‑house or private network that uses Internet network protocols. Because they are limited in scope, intranets generally use higher‑quality communications lines than standard telephone lines, so they are usually much faster than the Internet.

Streaming video over the web

Though there are fewer users with dial‑up connections than in previous years, you should still consider tailoring your data rate to users still employing this method of accessing the Internet if you want your file to be viewable to the largest number of users. Streaming video on the web is constrained by the limited bandwidth (56 KB or less) of most consumer modems. Use a higher bitrate if you know your audience has broadband Internet access, such as DSL or cable modem service.

Playing back from a handheld device

The data rate is very important due to the relatively small size, capacity, and lesser speed of handheld devices. The data rate can range from 8 to 90 kilobits per second, depending upon the device. You can choose preset QuickTime export options in Premiere Elements to export a file optimized for playback on a handheld device.

Downloading a video file over the web

The data rate is less important than the size of the video file because the main concern is how long it takes to download the file. However, it still may be desirable to reduce the data rate for downloaded video because doing so reduces the size of the video file, making it download faster.

About compression keyframes

Compression keyframes are different from the keyframes that you use to control track or clip properties, such as audio volume or clip rotation. When you export a movie, Premiere Elements automatically places compression keyframes at regular intervals in the movie. During compression, these keyframes are stored as complete frames. The frames between the keyframes are called intermediate frames. Premiere Elements compares each intermediate frame to the frame before it and stores only the data that is different. This process can greatly reduce file size, depending on the spacing of the keyframes. Fewer keyframes and more intermediate frames result in smaller file sizes with lower-quality images and playback. More keyframes and fewer intermediate frames result in significantly larger file sizes with higher-quality images and playback.

For example, a video of a talking person has a smaller file size than a video with lots of action, because only the mouth and tiny facial expressions change frame to frame. In contrast, a video of a sporting event requires numerous keyframes and intermediate frames, because the action changes considerably frame to frame. This results in either a larger file size or lower quality playback, depending on how much you compress the video.

Choosing compression settings is a balancing act. You need to adjust the setting depending on the type of video material, the target delivery format, and the intended audience. Often, the optimal compression setting is arrived at through trial and error.

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