How to Compress Video on Mac

That screen recording might be 600 MB for five minutes. Email and upload forms fail long before anyone watches it. You usually need a shorter clip, a lower resolution, or both.

Why video files get so big

Phone and Mac exports often save every frame at high quality. Screen recordings with small text need more data than a talking-head clip.

What you recorded	What usually helps first
Long QuickTime capture	Trim the start and end
4K export	Export at 1080p for sharing
Master from an editor	Keep the master, compress a copy

A MOV from QuickTime or an iPhone export is often H.264 or HEVC at full resolution with little trimming. Five minutes at 1080p can land near 500 MB before you change anything. If the portal rejects the file, the fix is usually shorter runtime, lower resolution, or a more efficient codec, not a magic one-click slider.

Bitrate, resolution, and frame rate basics

Three settings drive most of the file size you see in Finder.

Setting	What it controls	Practical tip
Resolution	Pixel width and height (720p, 1080p, 4K)	Downscale 4K to 1080p before chasing tiny CRF values
Bitrate	Data per second of video	Lower bitrate = smaller file, more visible compression
Frame rate	Frames per second (24, 30, 60)	Screen recordings rarely need 60 fps for Slack or email

Resolution is the fastest lever. A 4K screen recording shared at 1080p often looks fine on a laptop and can cut size sharply. Bitrate matters when you keep the same resolution: QuickTime export tiers map to approximate bitrates, while FFmpeg CRF lets you pick quality directly. Frame rate is easy to overlook: exporting a 60 fps capture at 30 fps halves frame data when motion is slow.

For MOV sources that fail on upload sites, converting to MP4 with H.264 is a common next step. See the MOV to MP4 guide when the problem is format, not just size.

Compress in QuickTime or iMovie

QuickTime Player:

1. Open the video.
2. Edit → Trim (⌘T).
3. File → Export As… → 1080p or 720p.

iMovie: import, trim, File → Share → File…, pick resolution.

QuickTime is fine for one clip. You cannot set an exact megabyte cap or queue twenty files. For a single handoff, trim dead air at the start and end first. That alone can drop a rambling screen recording below an email limit without touching quality settings.

Compress with FFmpeg in Terminal

Open Terminal (Applications → Utilities → Terminal). Install FFmpeg through Homebrew (if brew is not found, install Homebrew first):

brew install ffmpeg

Open Terminal, paste (edit filenames):

ffmpeg -i input.mov -c:v libx264 -crf 23 -preset medium \
  -c:a aac -b:a 128k -movflags +faststart output.mp4

Flag	Plain meaning
-crf 23	Quality (lower number = better, bigger file; try 20 to 26)
-preset medium	Speed vs compression tradeoff
-movflags +faststart	Better for web playback

VLC can also convert video (File → Convert / Stream), but picking the wrong profile is easy if you are not used to it.

To downscale and compress in one pass:

ffmpeg -i input.mov -vf scale=-2:1080 -c:v libx264 -crf 23 \
  -c:a aac -b:a 128k -movflags +faststart output-1080p.mp4

FFmpeg shines when you have a folder of clips and want the same settings on each. For one-off sends, QuickTime is usually enough.

Email and upload size limits

Limits change, but these ranges show up often enough to plan around.

Destination	Typical limit	What usually works
Email (consumer)	10 to 25 MB	Trim + 720p, under 2 minutes
Slack (free tier)	1 GB per file	1080p for most clips
Issue trackers	10 to 50 MB	Short clip, 720p, or split the video
Client portals	25 to 100 MB	Check the form; trim or lower resolution
Social uploads	Varies by platform	Follow platform specs; re-encode if rejected

When a form shows a hard megabyte cap, guessing export tiers is frustrating. Note the limit, trim the clip, then export at 720p. If it still fails, shorten the runtime or switch to a dedicated compressor with target file size for video.

Pick settings for where the file goes

Where it goes	Starting point
Email	Trim + 720p
Slack or Drive	1080p
Portal with a size cap	Shorter clip, or use target file size in GetCompress

Watch text and faces on a laptop screen before you send. Screen recordings with UI text need a quick check at 100% zoom. If edges look soft or blocky, back off one quality step or keep 1080p instead of pushing bitrate lower.

For broader cleanup across Downloads and project folders, the reduce file size on Mac guide covers video alongside photos and PDF.

Using GetCompress

GetCompress handles MOV, MP4, and other common video formats locally on your Mac:

• Drag one file or an entire folder into the queue and apply the same preset to every clip.
• Set target file size on video when a portal lists a megabyte cap; the app adjusts encoding toward that limit.
• Trim start and end in the preview player before export so you do not re-open QuickTime.
• Save presets (720p email, 1080p Slack, review quality) and reuse them on the next batch.
• Process files on your machine only, which helps when the clip shows unreleased product UI or client work.

GetCompress is an easier alternative when QuickTime presets are too coarse and you do not want to maintain FFmpeg one-liners for every send.

Before delivery, use the synchronized video comparison tool to play the source and compressed export at the same timestamp and inspect motion, text, and gradients.