These days, your smartphone, your DSLR camera, and your GoPro can all shoot high-quality, high-resolution video — but wow, the size of that video file can sure balloon quickly.
You will feel the pain when your memory card maxes out or you want to upload one of these videos to share on the Internet.
The good news is that you can reduce video file sizes fairly easily. The bad news is that unless you change the right settings, you will lose video quality. How do you balance the two? Which settings should you change to get reduce size without compromising quality? Read on to find out.
1. Pick the Right Software
You really should use a computer for this task, not a tablet or a smartphone. The powerful desktop tool Handbrake is the most useful cross-platform media convertor out there. It’s completely free and works the same on Windows, Mac, and Linux.
If you’re on Windows, you can also try the Freemake Video Converter, which has an easier interface. However, Handbrake does a better job of encoding and converting videos, so I would recommend learning its interface and going with that instead.
Meanwhile, if your video has issues, try a video quality enhancer to iron those out first.
Download: Handbrake for Windows, Mac, or Linux (Free)
2. Start With the Audio
Before you begin chopping down the quality of your video, head to the “Audio” tab in Handbrake. You might be surprised how much space audio channels take up. Unless you’ve shot a concert, always tackle the audio first.
For any video where human speech is important or music isn’t a priority, here’s what you need to do.
- Check if there are more than one audio tracks. You just need one. If it’s a movie file, look for the “English” audio (or whichever language you want). If it’s a video you made, the first track will probably be the right one. Delete all the other tracks.
- In Codec, choose AAC (CoreAudio) or MP3. These are lossy compressed audio file formats that are good enough for most cases. In fact, even for concerts or other such videos, you can choose one of these lossy formats and sample it at a higher bitrate.
- In Bitrate, choose 160 by default for most videos. Choose a higher bitrate (256 or 320) if you’re converting a video where music is the main element.
I would recommend that you don’t mess with the sample rate and simply set it to Auto, but it can be tweaked to optimize audio file size. For human speech, set the sample to 32, and if music is important, set it to 48.
3. Choose the Best Codec and Container
Ideally, the original video you shoot should be using the highest quality video codec and container. When you’re ready to reduce the size, you pick the most efficient codec and container.
What’s the difference between the two? Basically, the codec is the encoder/decoder that turns a video into bytes (the “brain” that determines the base quality) whereas the container is the file format (the “body” that determines compatibility with different devices and services).
Choose H.264 as the codec. This is the most efficient and popular codec for high-definition videos and is said to be almost two times as good as MPEG-4 in compressing videos. It is also recognized by most devices today, be it a simple TV or the Raspberry Pi.
As of this writing, you don’t really need to bother with its successor, the new H.265 standard.
Choose MP4 as the container. Again, MP4 is efficient, but more importantly, it’s the most widely recognized file format for videos. In fact, YouTube, Vimeo, and Facebook recommend MP4 as the preferred container.
4. Reduce the Video Resolution
It’s great that your phone can shoot 4K videos, but do you even have a 4K-ready TV or monitor to play it on? Most people have HD Ready or Full HD TVs, but the big secret is that video resolution isn’t as important as you might think.
Resolution affects the size of the video greatly, but the quality may not be greatly affected. How far you sit from the screen, the upscaling technology of the TV, and the bitrate of the video are going to have as much or greater impact.
Here’s a list of commonly-used resolutions:
- 2160p (3840×2160)
- 1440p (2560×1440)
- 1080p (1920×1080)
- 720p (1280×720)
- 480p (854×480)
- 360p (640×360)
- 240p (426×240)
As a thumb rule to reduce file size by resolution, check the video’s original resolution and choose one level below it. In Handbrake, you will find this in “Picture Settings” in the top-right menu. You can even check out a Preview of the lowered resolution before you commit.
If you plan to simply upload your video to YouTube or Facebook, then 720p is the best way to go (assuming file size is more important to you than resolution). Facebook even caps the resolution at 720p but YouTube lets you go higher till 4K.
5. Bitrate Is the Last Resort
The biggest factor in determining the quality of a video is its bitrate, so make that your last resort. In simple terms, bitrate is the amount of data being shown in one second. The more data you allow, the more artifacts can be shown on the screen, and the better the video quality will be.
Most DSLRs record video at high bitrates as do most screen recording and screencasting software. Again, YouTube has some recommended bitrates that you can use as a thumb rule for any video file. Don’t go below these recommended numbers, but if your current bitrate is higher, you can safely reduce it.
It’s best to keep your bitrate variable rather than constant. In Handbrake select Video > Quality > Average Bitrate, and key in a number that best corresponds to your video’s resolution, using the above chart. Also check the box for 2-pass encoding.
6. Don’t Change Frame Rates
If anyone tells you that you should reduce the frame rate, don’t listen to them. Every video expert, video hosting site, and video editor says that you should keep your video at the same frame rate that it was recorded in.
The human eye only needs 24–30 frames per second (FPS) for a decent picture, so it might seem logical to lower the frame rate to that range. However, doing that can affect the smoothness of the video, and especially make movement seem jerky or unnatural.
So avoid this unless you are experimenting with slow-motion videos.
Got Any Other Tricks to Share?
With this guide, you should be able to substantially reduce the file size of a video without greatly affecting the quality. Remember, go step by step, you might hit your intended target size much before you need to reduce the resolution or the bitrate. What tricks do you use to bring down the size of a video that you want to share?
And if you perform your editing on your mobile device, check out these free video editing apps for iPhone and iPad.
Image Credits:scale pan by kulyk via Shutterstock