If you use iMovie to edit videos quite often, you might have experienced the same dilemma as reading the following iMovie user: I trimmed a video that was about 920MB, then I exported it, the size jumped to over 9GB. How could this happen? iMovie does a lot more than editing. Here's our guide on how to compress video with iMovie.
Compress videos from 1GB to 10MB with good quality reserved thanks to High-Quality Engine. Compress video in several ways. You can trim, cut, adjust the resolutions, bit rate, video codecs, quality etc. Part 1. Step 1. Step 2. Step 3. Step 4.
Part 1: Preparing and Importing Media
You have several ways to import videos you'd like to resize in iMovie. Import a video by directly dragging it from Finder. Select a single file or command-click to choose multiple videos, or pick a file folder and drag them to an event in the Libraries list in iMovie. Alternatively, open the Import window, click the download arrow in the toolbar and select files to load. Ways are slightly different for different versions. iMovie for Mac now supports to import HEVC 4K video.
Step 2. Edit videos as you like with iMovie. Follow our iMovie video editing tutorial to split clips, insert transitions, crop videos, create the fade in and fade out effects, and more. Note that video editing possibly affects output video file size. You can skip this step if you don't need to do any video editing on Mac or iOS devices and just directly move to the next step.
Part 1: Reducing File Size Through Resolution and Quality Settings
Step 3. Video length and bit rate determine file size. So the first way to make video size smaller in iMovie is to trim your video. You can trim clips in the timeline by simply dragging to remove an unwanted part and shorten the video duration. To do so, in the timeline, review your video to ensure the video clip you want to remove and drag the video toward its center to move the video start point and end point. You can also remove frames from the video, just go to Window > Show Clip Trimmer, drag the edge toward the clip's center.
Step 4. Click Share icon in the toolbar, and click File at the top. On the File window, there are various video options like description, tags, format, resolution, quality, and compress. Format, resolution, quality and compress settings affect final output video size. Click the format menu and choose a smaller-sized video audio format, in fact, codecs instead of container formats influence video file size, check out the list of best video codec for video compression. Click Resolution pop-up menu and lower down video resolution to shrink video size in iMovie. 4K delivers four times the file size of 1080p HD video, and 1080p twice the size of 720p, consuming other settings are the same. You can convert 4K to 1080p/720p, 1080p to 720p in iMovie to get smaller sized output without noticeable image quality loss. Meantime, click the Quality drop-down icon to decrease the quality. You can manually adjust the video bit rate by picking Custom option under Quality menu. The final step is to choose an iMovie export compression setting. Select an option. Better quality will result in larger file size. And click Next to close the dialog and move to the next step.
Step 5. Enter the file name, choose a location for the output, and click Save. You'll see a progress indicator, click it to check more details. The indicator disappears once the whole process is done.
Part 2: Understanding Why iMovie Files May Get Larger
iMovie File Size too Big? Many users reported that video files got bigger after editing with iMovie even if they trimmed the video. When you export videos with Best Quality, you will get a larger video file. If you export at just Good Quality, the output file size is smaller. Higher quality means higher bitrate and larger file size. When a clip is imported into iMovie, iMovie unpacks (decompress) the video file for editing, which makes the video become larger. You can export video in a more compressed format, such as MP4 instead of pro res for iMovie. When exporting videos in iMovie, set the Resolution to lower one, Quality (Custom), Compress (Faster), and adjust the video bitrate slider bar to reduce the bitrate. It will be a much smaller file size but also worse quality now.
iMovie is not the best video compression software for Mac; sometimes it goes wrong. 3 out of 10 users encounter issues such as iMovie not exporting, iMovie crashing when exporting, or terrible compressed video quality. You have many better iMovie alternatives to choose from, and Macxvideo AI is a popular option. The high-end video compressor is available for both Windows and macOS. It can reduce the file size of 8K/4K/1080p/720p HD video by up to 98% with 5x faster speed than iMovie thanks to its unique compression algorithm, embedded High-Quality Engine, and support for Intel/AMD/Nvidia hardware acceleration. You are offered various video audio options to resize big video files, for example, bit rate, frame rate, resolution, codec format, trimming, cutting, aspect ratio and more, together with preset profiles for YouTube, Vimeo, DVD, iPhone, iPad, mobile devices etc.
Part 3: Practical Workflow with iMovie and Alternatives
Candice Liu Candice's particularly skilled in writing and sharing video-related contents. Her guides cover from deep-seated video/audio parameters, to media entertainment on different platforms. If you're finding that iMovie exports result in files that are too large, you're not alone. The solution? Never used iMovie's compression feature before? No worries! This guide will take you through the process of compressing a video in iMovie step by step. Part 1. Before we get into the subject, please have a check on your iMovie version. Some minor differences exist among different iMovie versions during the actual compressing procedure. Step 1. Step 2. Load video file to iMovie. Hit the button with downward facing arrow on the upper left corner of iMovie window. Drag your video to the editing area with extensive gray area on the bottom of the iMovie interface. Step 3. iMovie offers you the editing features split and cut for compressing video. Split a long video into clips with average length and you can just pick up one or some clips. Cut the unwanted footages from your video to reduce video file size. Step 4. At the upper right corner of iMovie main panel, find out the icon with a upload icon and click it. Or in other versions of iMovie, go to the menu bar of your MacBook/iMac, tap "File" > "Share" > "File...". Resolution: 720p or 1080p is recommended. Quality: 3 options are available: Low, medium and high. Compress: Faster or Better Quality. For high-end computer and video input with short length (less than 1 hour), you're suggested to prefer Better Quality. As for large-sized yet hi-def 4K/8K video in long length, faster is preferred. High resolution and high quality are inversely propotional to video size. But highly compressed video file will result in poor quality. Step 5. Save your file. Tap "Next" after the settings are done. Name your resulting file and find a place to save your file. Step 6. Find out your iMovie exporting file and compare its size with the previous size.
1. Inability to Adjust Bitrate: iMovie doesn't have manual control over the video bitrate, the most critical factor determining file size and quality trade-offs. 2. Quality/Size Trade-Off: iMovie relies on general resolution and quality presets (e.g., "Best Quality"), which often result in unnecessarily large file sizes. No Two-Pass Encoding: It also lacks advanced compression methods like two-pass encoding, which would significantly improve the quality-to-file-size ratio compared to its standard, faster single-pass encoding. 3. Dependency on the Apple Ecosystem: While integration is seamless, iMovie's focus on simplicity limits features readily available in professional tools, making it inadequate for users requiring specific compression standards or advanced codec handling.
Part 2. iMovie's compression workflow sacrifices professional control for user simplicity, creating issues when users need optimized file sizes for storage, web upload, or external sharing. So you may want an iMovie alternative for better video compression. Winxvideo AI works as a good replacement when it comes to compressing video. You can compress multiple files at once and directly target the file size by moving the slider simply without burdening the CPU, thanks to the full utilization of GPU acceleration. It also supports the most advanced encoding standards like HEVC, AV1, and H264. This allows for best efficiency and makes it a good choice for web uploads and long-term archival storage. Unlike iMovie that just offer simple compression, Winxvideo AI also allows you to fine-tune parameters like resolution, fps, bitrate, GOP, two-pass encoding in the Converter module. So whether you want simple presets optimized for specific platforms like YouTube, or granular control for superior compression results, it will cover your needs.
Step 1. Free download this video compressor and install it on your macOS or Windows. It's 100% safe, clean and virus-free, no bundled 3rd party software, plugins or adware. Step 2. Step 3. Click "+Video" button at the upper left corner of the home screen and opt for the video file to load into this tool. Bulk compression is available. An expansive library of input formats are supported, MP4, M4V, MKV, MOV, AVI, FLV, WMV, MTS, HEVC, VP9, H.264...
Step 4. Simply drag file size slider bar. Then cut video length (lossless compression, as well). Enable Trim to freely set the start time and End Time to shorten your video length, or drag the slider to the video section you want to keep. Step 5. Choose your desired video resolution, compression video or audio codec like HEVC, AV1, AAC, etc as output codec, and format MP4, MKV, MOV as per your needs. Step 6 (Optional). You can also go back to the main interface and click Converter to further adjust video resolution, bit rate, frame rate, etc. (lossy compression). On the video info window, tap the gear-shaped Settings button to get more options to tweak your video parameters for smaller file sizes. Generally speaking, compress 4K to 1080p, lower frame rate from 120FPS/60FPS to 30FPS, and adjust bit rate. These will further compress your video at high compression ratio. Keep in mind that do not lower down them too much. Step 7. Click the RUN button to start reducing video file size even from GB to MB with virtually no quality loss (High Quality Engine support).
How To Compress Video Files With Apple Compressor
Warm prompt: for iPhone iPad users who demand to compress videos, transfer iPhone iPad videos to computer and use the above video reduce software to do the shrinking task. iMovie for iOS can make video size smaller, but it doesn't you the file size and aspect ratio after using cropping feature. Desktop video compressor program is much better than iMovie for iPhone iPad esp.
Practical Tips to Optimize iMovie for Smaller Exports
- Export settings matter: Better Quality yields larger files; choose Good or Custom to reduce size.
- Resolution is king: 4K exports are much larger than 1080p or 720p; downscale when possible.
- Use trimming and splitting: Removing unnecessary footage reduces length and size.
- Compression format matters: Export as MP4 with H.264/HEVC rather than high-overhead containers.
- Two-pass encoding not available in iMovie: If you need aggressive compression, consider an alternative tool that supports two-pass encoding.
From the Projects browser, tap the video youâve compressed and you want to share. If you are editing the video, tap Done in the upper-left corner. iMovie offers compress settings: Faster or Better Quality under the Export settings. Faster means smaller file size but worse quality. Better Quality means larger file size. Quality has options: Low, medium and high, which can also be used to compress video in iMovie. Resolution options are also good ways to reduce video size in iMovie. If you export video with the Best Quality (pro res), you will get a video file several times larger.
Whatâs the best way to compress video on a Mac without losing quality? The guide presented here compares iMovie with capable alternatives like Winxvideo AI and Filmora, offering practical steps to trim, adjust resolution, and select appropriate codecs to achieve efficient compression while maintaining acceptable visual fidelity.