Setting Up Video Quality

Permute comes with some default settings that are fine for most users, but each use case has its own goals and priorities, which is why there are settings for you to customize. This help page will try to explain some basic principles and includes various tips and tricks. All of these settings relate to preset settings that can be found in Settings > Presets.

Starting with Permute 3.12.1 when running macOS 13 or later on an Apple Silicon hardware, Permute will use, by default, Constant Quality settings which produce good quality results with small file sizes for H.264 (used e.g. in MP4) and H.265 (HEVC).

Tips and Tricks

• Bitrate defines how much space on the disk will the final file take up. The lower the bitrate, the smaller file, but usually worse quality.
• Constant Quality (CQ) and Constant Rate Factor (CRF) are options available on several video formats (H.264 and H.265/HEVC) and allow you to control the quality rather than exact bitrate. This is a much better option in many cases unless you need a more consistent bitrate in case of e.g. Internet streaming.
• Videos that are mostly still (e.g. slideshows, security camera video, etc.) require lower bitrate to achieve the same visual quality than videos with a lot of movement (e.g. movies, home videos, etc.).
• There are several factors that you may consider: file size, speed of conversion, visual quality. These usually go against each other - if you want a small file with good visual quality, the conversion will take longer, if you want great visual quality, but are OK with it taking up more space, the conversion will be faster.
• On macOS versions prior to macOS 13 or on macOS versions runnning on Intel CPUs: Hardware-accelerated conversions usually take up more space as the hardware acceleration cannot “reason” that much about the content and the data compression is lower. If your goal is to make as small files as possible, it is recommended to turn off the hardware acceleration. Without the hardware acceleration you will get better quality with the same bitrate, but it will be slower.
• Starting Permute v3.6, you can set target file size for video files in group options.

Setting Up Permute

Initially, try setting the Video Quality settings to one of the Low/Medium/High/Ultra options and see if any of those meets your demands. If yes, great.

If you need, however, more control about the size-quality ratio, this is where the Custom option comes in. Please keep in mind that the higher the bitrate, the better quality, but the larger file. And the same goes for the opposite direction. What you need is to find the sweetspot that works for you.

When you set the video quality to Custom, depending on the format and OS that you’re running, you can see several options:

• Constant Quality (CQ) - this option ranges between 0 (worst) and 100 (best) and controls the quality rather than bitrate. Default is 50 which outputs good results with small resulting files. This is unavailable if hardware acceleration is enabled on macOS versions prior to macOS 13 or when running Intel CPU.
• Constant Rate Factor (CRF) - this is similar to CQ (there are slight differences, but let’s not get into those), but the scale is a bit different - it ranges between 0 (best) and 50 (worst). Around 25 is a very decent value, 30-35 is for a faster conversion, smaller files, but slightly worse quality. This is unavailable if hardware acceleration is enabled.
• Bitrate - you specify both Bitrate and Maximum Bitrate (if applicable, depends on video format). The values to enter depend on several things:
  • the input videos (resolution, amount of motion – still videos are fine with lower bitrates, videos with a lot of movement not so much).
  • everyone is aiming for something a bit different, it’s not possible to recommend one value that will satisfy everyone.

The general advice when setting bitrate is:

• start with a value that is targeting your desired file size – for example, if you want to reduce a 10-minute (600 seconds) to 50MB, you need bitrate that is (50,000 (kB) / 600 (seconds)) * 8 (8 bits per byte) which gives a bitrate of ~666kbit/s
• keep maximum bitrate 10-20% above bitrate depending on the amount of action (if you see blockiness during scenes with more movement, increase the max bitrate). If your video has limited motion, you can try lower values
• run the conversion on some sample video that is short (~1 minute) and see if you are satisfied with the result. If not, increase the bitrate. If yes, try decreasing it (try 50-100kbit/s at a time) until you find the sweetspot you are looking for.
• starting Permute v3.6, you can set target file size for video files in group options

Please note that this is very individual and everyone has the sweetspot somewhere else – this is why Permute has these options. Everyone has a different goal and is willing (or not) to sacrifice some quality for size.