Nate Thibodeau (Simba) writes:
I use HandBrake for most of my video encoding needs, but I am confused by the two quality options that can be used: Constant Quality (RF:#) or Avg. Bitrate (kbps) (single or two pass).
I see these options (or something very similar) in other encoding software as well. I have read some info on how each mode works, but I am looking for some input for some professionals who know much more about video encoding than I do.
Which of the two modes produces the best quality vs. file size or vice versa? Is one technically better than the other? What type of encoding method do the pros use?
This is a good question, and before I get into exactly which of these solutions might be better for you, I would like to point out that there is a difference between commercially licensed codecs and open source codecs commonly used via HandBrake. HandBrake is a free solution that works great for most home users. The problem with HandBrake is that (though it does produce decent video) it doesn’t exactly fit the description of something someone would use at a professional capacity. If you’re wondering what the pros would use, you might be better served by either Compressor on OS X or Adobe Media Encoder on Windows or OS X.
With that out of the way, there are two ways you can go about getting decent video from HandBrake using the options you’ve highlighted here.
Average bitrate is great if you have a specific file size in mind and are willing to give HandBrake more control over the quality of the content. The goal of this mode is to keep the data stream steady in order to meet your goal file size in mind. You might end up with less clarity during intense action scenes and perfect clarity during scenes with little overall movement. Unless you set the goal bitrate high enough, you’ll probably end up sacrificing quality using this mode. You might want to utilize multi-pass encoding to get the most out of your bits. This takes more time but the results are typically more pleasing to the eyes.
Constant Quality gives you more control over quality and less control over the size of a file. You could crank it to the highest setting and throw caution to the wind. HandBrake will determine how much data is needed to meet that quality demand and set the file up to meet it. Constant Quality can produce the same quality as a multi-pass encode in a single pass. This makes rendering a little faster.
During scenes where less action is happening on screen (steady camera and one or two subjects moving across a stationary background), the bitrate can be spared with a higher bitrate stepping in during scenes with high action and more pixels moving across the screen from frame to frame. Depending on which of these choices you decide to use, the bitrate will either rise or fall as needed. Average bitrate is limited by definition, but you won’t get stuck with a 4 GB file when you really need a 700 MB one.
HandBrake is a great tool for anyone wishing to encode video on a budget. It works with a multitude of different formats and performs like a champ. Just don’t expect it to be the best answer if you’re hoping to use its output at a professional level.