How Do You Compress Large 4K/HD Video on Mac? Find Answers Here

Best Tool to Compress Oversized 4K/2.7K/HD Video on Mac with No Quality Loss Visually

MacX Video Converter Pro is a professional video converter and compressor that can make video to 90% smaller automatically and manually with maximum image quality kept. You can convert among 200 video formats, and reduce video size by tweaking video resolution, bit rate, resolution, codec, frame rate, and more to suit your Mac, iDevice, Android, social sites and more.

Table of Contents

• Part 1. Why Is Compressing Video Important?
• Part 2. Do You Know the File Size of Video You Shoot?
• Part 3. What Affects Video Size?
• Part 4. How to Resize/Compress Video For Different Uses
• Part 5. Are There Any Other Apps to Compress Video File?
• Part 6. External Sources: How Video Compression Works

Part 1. Why Is File Compression Important

Videos are great but they can also cause headaches. Here are some scenarios:

• You were once crazy about your birthday gift GoPro Hero 6 Black and shot massive extreme sports footages, which easily steal away your hard drive space and slow down your computer but you are unwilling to delete them at all.

• You did some content creation with your DJI P4P when travelling in England but found it too big to email your grandpa and even run into choppy or broken up playback when viewing it because it is oversized.

• You just want to share a funny video of your 5-month baby from your iPhone X but it took you hour to upload to YouTube and even stuck.

• You scored some memorable moments for your graduation ceremony using a Canon 4k-enabled camera, but what's frustrating is when you try to send them to your friend via whatsapp, it prompts a message of too large file size.

No more bothering. Compressing video will solve all the problems. It can:

Maximum storage space of hard drive/mobiles/cloud service

File compression reduces the amount of space required to store the video data. This is especially beneficial if you have a space-constrained mobile device. For example, a 64 GB iPhone will hold a 4K UHD video as long as 5 hours when compressed using HEVC codec, but less than 2 minutes for uncompressed raw video will devour your iPhone's space. Deleting the video is a temporary solution while using video compression to resize video will solve the problem once and for all and therefore make more room to store more videos.

Follow the guide if you want to free up some space on iPhone >>

Send video via Email, Whatsapp, etc with no size limit

Almost all email systems put limitations on the video size attachments. For example, Gmail and Yahoo only allow for 25MB video sending while Outlook and iCloud mail impose a limit of 20MB per video. If the video exceed the limitation, it will be slow, require you to upload to Google drive, and even receive an error message. So compressing video to reduce the amount of data to reasonable size will make it easy and quick to transfer via mail.

Click to learn how to compress and send large video over email >>

Upload video online as fast as possible

The size of the video plays a decisive role of the amount of the time it takes to distribute over the internet. Generally, the upload speed is around 1.5 mb/s. You can also test your internet connect and find your upload speed with speedtest.net or testmy.net. Accordingly, the amount of time required to distribute over the internet at 1.5mb/s bandwidth will be calculated as follows:

• A reasonable 500 Mb video will takes around 5min33s to upload online;
• A 1 Gb video will consume 11min22s for distribution;
• A large 1.5 Gb video will need as long as 17min4s.

Note: The internet connection is not as exactly as your expect. So the upload time will float up or down. So you are for sure unwilling to waste your time in uploading. By downsizing the large video into a smaller one, it will greatly reduce the amount of time it takes and lower the bandwidth required to transmit the data.

Follow the guide to compress and upload big video to YouTube >>

Play videos on whatever device screens flawlessly

There are times you cannot play videos on your mobile phone or tablet successfully, even though your gadget supports FHD video resolution and various video formats. Chances are some video files you want to view are from camcorders, online sources, to name a few. They are shot at different settings, e.g. the video resolution goes beyond your device screen, the bit rate is as high as 1000 Mbps which, as a result, ends up being queerly large size and quickly chews up your device storage space. This is why you need to resize video and rescale the video dimension in such a way to decrease the video size and fit your device's display properly.

Archive and backup videos fast and easily

Backing up and transferring videos from one computer to another is as easy as copy and paste. But if the videos are several gigabytes in size, to compress the video files will greatly save your time and thus save storage space. Besides, the compression involving in video format transcoding will also ease the process from Windows platform to macOS computer.

Wanna backup video between iPhone and Mac, here is the tips >>

Part 3. What Affects Video File Size?

Before we go further into the file size section, there is a formula you should know:

Time (second) x Bitrate (kbps)/8 =Video Size (kb)

For instance, the file size of a 90min 720p H.264 video at 3.4Mbps is equal to: (90x60) x (3.4x1024)/8=2350080Kb = 2295Mb = 2.24 Gb

Note: A video file comprises both image and audio, which use different bitrates respectively. So the bitrate in the formula refers to the sum of audio and video bitrates ; 1 Kb = 1024 bit, 1 KB = 1024 Byte, 1 Mb = 1024 Kb, 1 MB = 1024 KB, 1 Byte = 8 bit, 1 MB = 8Mb, 1 Mb = 0.125 MB.

What Can We Learn from the Above Formula: From the above formula, the decisive factors affecting the video file size are the bitrate and length of the source video. However, the bitrate vary with resolution and frame rate to some extent. Besides, there are still some factors give an indirect impact on the amount of data needed for representing the video, including the type of media format, color depth used in the image, sampling rate, video codec, and even subtitles. Below are the details.

1. Video Length Decides the File Size

It's beyond all doubt the video file size can be guesstimated based upon the length of the video. Longer video file will make a direct contribution to larger file size. Generally, cutting down the video length and removing the unnecessary segment of your video will help to resize the video to a smaller one. For example, a FHD MP4 video at a length of 2:34:23 will downsized from 5.9Gb to 5.6Gb when 9min video segment is removed from the source content. This is also a good way to shrink video size without causing quality loss.

Wanna cut/trim video to reduce file size? Check the answer >>

2. Lower Bitrate Brings Smaller-Size Video

Video goers may be not strange with the bitrate. Here are statistics - YouTube encodes videos with VP9 at a bitrate of 18Mbps, Netflix requires 15Mbps for H.265 video encoding, Comcast broadcasts video with H.265 at a bitrate of 18-22 Mbps. So what is Bitrate? Does it have something to do with the video file size? Can you compress and resize video by adjusting the bitrate. Here is the answer.

Bitrate is the number of bits per unit of time during data transmission. It's symbol of bit/s. It plays a decisive role in video quality during video compression. Bitrate involves in CBR (constant bitrate) and VBR (variable bitrate). The former keeps the bitrate the same during video encoding, which is helpful in multimedia streaming and processes data faster than VBR. However, CBR is on the hip for the quality instability of the encoded content, whereas VBR is effective especially when the content to be encoded contains both simple and complex areas, such as the video switched between fast motion and slow motion. Thus, video encoded with VBR is smaller and even half of the file size, and outputs better quality at the same file size. However, it consumes more time to encode video compared with CBR.

Generally a higher bitrate means a less media compression ratio, which accordingly accommodates higher image quality in the video output. But bitrate is proportional to the video file size. So lowering the bitrate will greatly cut down the video size, this being considered as a great way to compress video for small size purpose. (see how to change video bitrate to shrink video size >>)

Does Highest Video Bitrate Give Rise to Best Result?

Theoretically, it is. However, when the bitrate rises to a certain extent, going beyond what our naked eyes can distinguish, there is almost no quality difference. So when setting the bitrate to reduce the video size, it has the optimal value. Here is the recommendation with H.264 codec in accordance with the video resolution.

• • Supposing the video resolution goes to 1280x720p, the bitrate is preferably 3500Kbps.
• • When the video resolution reaches to 1920x1080p, set the bitrate at 8500Kbps. But some reaches to 30mbps, take MKV H.264 for example.
• • If the resolution of the video is 3840x2160p, the bitrate shall be optimized to 15-20Mbps.
• • For the HEVC encoded video, the bitrate can be around 10-15 Mbps.

Note:
1. Upping the bitrate disproportionately will increase the amount of data, thus wasting the memory space.
2. Decreasing the bit rate improperly may produce awful video quality.
3. If the video source is bad, no matter how you improve the bitrate, the video quality will not be elevated, but the file size will increased.

3. Advanced Codec Downsizes Video File

There are many video compression technologies, including H.261, MPEG-1 MPEG-2, H.263, MPEG-4, H.264, and the newer VP9 and HEVC, among which H.264, VP9 and HEVC are the most popular.

• H.264

H.264 is also known as MPEG-4 AVC or MPEG-4 Part 10, which uses CAVLC and complex CABAC (15% higher than CAVLC in the compression ratio) to remove coding redundancy. It applies interframe coding to eliminate temporal redundancy and intrafram coding to get rid of spatial redundancy. YUV420 is adopted to efficiently represent color images. H.264 offers good video quality and substantially lower bitrates of 50% compared with its previous MPEG-4 Part 2, H.263 and MPEG-2. As of 2014, H.264 is one of the most commonly used video file compression formats for recording, distributing and compressing video contents. It is popular as the video encoding standard for Blur ray Discs, used for low bitrate video streaming over Vimeo, YouTube, iTunes Store, as well as HDTV broadcast. Read more: how H.264 outperforms MPEG4 >>

• HEVC

HEVC is the successor of H.264. HEVC resembles H.264 in terms of coding frame, in which transform, quantization, interframe prediction, intraframe prediction, etc also exist but brand-new encoding technologies are applied to improve the compression efficiency. It is the best video compression standard for 4K and even 8K UHD. HEVC format is available in some camcorders like the latest GoPro HERO 6, new iPhone models supporting iOS 11, Mac computer updating to the latest High Sierra, Windows 10, and even some video encoder software such as VLC, Handbrake and MacX Video Converter Pro.

Compared with H.264, HEVC further doubles the data compression ratio - dramatically improve the video quality at the same bit rate or halve the video size at the same level of video quality. A 1 min MOV video recorded with iPhone will take up different storages when encoded with H.264 and HEVC, for example

• • It takes up 350Mb in H.264 but 170Mb in HEVC when the video is shot at 4k at 30 fps
• • It takes up 175Mb in H.264 but 90Mb in HEVC when the video is shot at 1080p at 60fps.

Take a look how HEVC outperforms H.264 in video size at each of the resolutions and frame rates Apple iPhone uses.

Tips: Compress iPhone 4K H.264 for smaller size

• VP9

Like HEVC, VP9 is another new video compression format that achieves 2x compression ratio gain compared with its predecessor VP8. The open and royalty-free format acts as a competitor against HEVC. VP9 is mainly used on Google's YouTube, which makes a sense YouTube doesn't include HEVC support. This pose a great problem when uploading a 4k UHD video if it is not encoded with HEVC, as the file size will easily exceed 128Gb that YouTube requires. Read more: VP9 vs HEVC

These video coding formats mentioned above involve in process of compression and are used to reduce the spatial, temporal, visual and coding redundancies in such a way to bring less amount of data and bandwidth saving. So by converting the video from older codec to advanced video codec like HEVC, the data in the video is rearranged in a more efficient way, thus the file size will therefore decrease. For example, you can just compress large 4K/HD videos by changing the video codec to the advanced one, such as H.264 to H.265, if your computer is well configured.

4. Do Resolution and Frame Rate Really Matter?

Resolution is a measure of the size of the pixels. Videos can be categories into SD, HD 720p, FHD 1080p, 4k and 8K UHD nowadays when it comes to resolution. Whereas frame rate refers to the frequency (rate) at which consecutive images called frames appear on a display. Most videos are presented at 24 or 30fps while 60fps is widely available for its life-like experience. The higher the number of frames, the smoother the video will display. But there is the real fallacy: video of higher resolution and frame rate will need more data to store more pixels and more data will be needed to accommodate the frames, thus resulting in larger file size. Is it the truth?

According to Gopro, a 4k 30fps video has a bitrate of around 60 Mbps but a 720p 120fps video owns only 30 Mbps. That's why you get a bigger video with higher resolution.

Here is another proven fact with iPhone H.264 video. From the image shown on the right side, we can clearly see that size of 1080p 240fps video is up to 480 Mb, 80 Mb larger than that of 4K UHD 60fps video. The former has a bitrate of approx. 64 Mbps while the latter is just 53 Mbps.

As a matter of fact, video resolution and frame rate have nothing to do with the size and quality, what matters most is the bitrate and video length. Bitrate increases along with the video resolution and frame rate in order to have the best video viewing experience. So we'd like to say both they play an indirect role in influencing the file size, rather than a direct determinant. Tests show the file size will be decreased slightly from 5.9Gb to just 4.5Gb when the video resolution is lowered from 2:34:23h FHD 1080p to 720p. And lowering the frame rate doesn't give any video size reduction at all.

5. Does Video Format Affect Size?

The container is also referred to as wrapper format that holds the video data, audio data, subtitles, and metadata of the video file. Most known formats include MP4, WMV, FLV, MKV, AVI, MOV, WMV,WebM, etc. MVK and AVI are popular for high quality but consume much space, whereas FLV, WMV and MP4 manage to offer smaller video file. For example, an uncompressed AVI will occupy as much space as 272 Mb but the FLV and MP4 only need more than 2 Mb to store the video file. The resulting file size also has a direct relationship with the bitrate. So it's a good way to convert video to MP4 at a lower bitrate with a video transcoder if you need to compress a video file.

See how to change video format to MP4 for smaller size >>

Part 5. Are There Any Other Apps to Compress Video File?

1. Mac Finder

Mac has built-in apps such as Mac Finder. It is the default file manager and graphical user interface shell used on Mac, which not only manage how you communicate with your Mac but also provide some unforgettable additional features such as effective compression of videos. You're free to reduce video file size without installing any third-party software.

Click File > Encode Selected Video Files > Choose the Settings (480p, 720p, 1080p, Audio Only, Apple ProRes) > Decide whether to encode video with Greater Compatibility or Higher Quality > click Continue. The format is going to be M4V, which is only applicable to Apple platform. The end result is satisfactory with file size reduced to 10.6 Mb at 720p, 5 Mb bigger than MacX Video Converter Pro at the same resolution.

Pros:

• User-friendly Interface
• It's fast, easy and free

Cons:

• Output format is only restricted to M4V
• There are limited options to compress video files.

2. QuickTime Pro

QuickTime is another Mac users favored tool offering easy access to video compression. You may watch videos or even make video with Quicktime, if you can reduce video file size with it, there is nothing better than achieving a lot at a stroke. It's suitable to downsize MOV and reduce MP4 file size. QuickTime Pro offers video shrinking feature at the cost of $30, here is the tutorial.

Step 1: Open the video in QuickTime Player.

Step 2: Click File Menu to select Export. This will open a window with several options from various resolution to iPhone iPad devices or iTunes etc. Choose your desired one.

Step 3: Rename your compressed video if you'd like to distinguish between the original and the compressed copy.

Pros:

• Easy to use

Cons:

• QuickTime is primary for MP4, MOV files only.
• It asks for $30 to compress media files.

3. iMovie

If you're at a loss on how to compress a video on Mac, you can turn to iMovie, one of the best video compression software on Mac since it's quick, free, and easy to use. This should take your video file and make it about one half its original size or smaller depending on what options you choose later. Here we go for reducing MP4 file size via iMovie.

Step 1: Import your video file into iMovie by clicking the "Import Media" button. This step may be slightly different for different versions of iMovie.

Step 2: Click and drag anywhere on the video strip until a yellow box appears.

Step 3: Adjust the size of the box and drag the selected section of video into the large gray area at the bottom of the window.

Step 4: Go to File > Share > File; Lower resolution and Quality to make a smaller file size; Click Next and name the file; then click Save to end the video files compression task.

Pros:

• Easy to use and free

Cons:

• Get errors such as a file compression error
• Slowed speed
• A mix-up of audio and video files

4. Clipchamp

Clipchamp, as one of the best online video compressor tools, is not only talented on converting, edit and recording videos, but also compressing videos online without the need to install third-party software. It is preconfigured with 4 profiles, covering Web, Windows, Mobile, and Animation GIF. You can directly upload the compressed video to Google Drive, Facebook, YouTube and Vimeo.

The compressing of video file with Clipchamp involves in: Click Convert Video File button > Sign up with a Google or Facebook account > choose a video to be compressed > select profile (Web, Windows, Mobile, Animation) and set the settings as per your needs > tap Start (you are also allowed to upload the video directly on YouTube or Facebook).

Pros:

• It's free and easy
• There is no annoying ads

Cons:

• Output formats are limited to MP4, VP8, VP9 and FLV, WMV, ASF and GIF.
• Signup is required to get access to video transcoding and compression.
• Grainy digitized quality appears for some time.
• Compressed video is watermarked.

5. VideoSmaller

The name of VideoSmaller gives a good explanation for the site. Working as a truly effective free video compressor without downloading a software, you can free to reduce the size of video online without compromising quality. Once you load the video by hitting the Browse button, it directly scales down the video resolution to the one you prefer in such a way to make video smaller. However, there are sometimes you might encounter 504 gateway timeout error during the process of resizing a video.

Pros:

• Support decent file format.
• Easy to use and understand interface.
• No registration required.

Cons:

• The size of the video to be compressed shall be less than 500Mb.
• Video compression won't work properly.

Part 6. External Sources: How Video Compression Works

The prerequisite for compression is there are some types of redundancy and irrelevancy in video dataset. The video type compression is meant to remove the wasted space consumed by storage media in such a way to reduce overall size of the media file.

1. Does the Video Have Redundancy?

Yes! The video redundancy can be categorized into 4 types.

• Spatial redundancy (aka intra frame redundancy). The nearby pixels of are correlated with each other. This usually happens in still image. The reduction of spatial redundancy is also called intraframe compression.

• Temporal redundancy (aka interframe/interpixel redundancy). When there are moving images like HDR, adjacent frames have the same values in the same location. Process of reducing the temporal redundancy is generally what we call interframe delta compression, which is the primary tech in data compression.

• Visual redundancy. Human eyes are generally insensitive to drastic changes of the video. This is a precondition for lossy compression at the expense of minor image quality loss that naked eyes cannot even distinguish.

• Coding redundancy. Uncompressed image is coded with the pixel at a fixed length. Compression is may be achieved with variable length code schemes such as Huffman coding.

2. How Is the Video Shrinked and Compressed?

Technically, the core technology of data compression is the removal of redundancies mentioned above. And compress methods can be sorted into lossless and lossy compression. The former involves in two-step algorithms, which transforms the original video to a format in which the temporal redundancy is reduced in the first step, and then the coding redundancy is removed with an entropy encoder in the second step. This method reaches a compression ratio of only 2:1 but it completely recovers the original video without any loss. Known for its high fidelity, lossless compression is especially important in the field of satellite and medical X-ray.

While lossy compression achieves a compression ratio as high as 50:1 at the cost of something unimportant based upon the ocular perception. The loss of video information cannot be recovered but the degradation of video image is still acceptable. Lossy compression is categorized into intraframe compression and interframe compression, each involving in few step algorithms in accordance with the 4 types of redundancy mentioned above. The former is specifically used for compressing the video within the one frame. The latter is adopted by more advanced video encoder, which derives from the correlation of neighboring frames, which encodes based on the vector difference between the current frame and the adjacent frames. Below are the process for general lossy video compression.

The Lossy Intraframe Compression Workflow:

• Step 1: Do away with spatial redundancy to pack the original video efficiently during transformation.
• Step 2: Use a quantizer to take out the visual redundancy so as to cut down the video bits.
• Step 3: Wipe out coding redundancy with entropy encoder for more efficient compression.

The Lossy Interframe Compression Workflow:

• Step 1: Remove temporal redundancy to pack the original video efficiently during transformation.
• Step 2: Get rid of the spatial redundancy during quantization.
• Step 3: Eliminate the visual redundancy with a quantizer to represent the video with as few bits as possible.
• Step 4: Wipe out coding redundancy and encode the quantized bits efficiently to get more compression.

Typically, MPEG-1, MPEG-2, MPEG-4, H.264 and HEVC standards are the examples of inter-frame compression. The graph on the right side shows how the interframe compression works.

Know more about interframe compression vs intraframe compression.