If you record audio with your video, make sure you factor that in as well. That way, you are again on the safe side when it comes to not running out of memory card space. If your camera uses variable bitrate, make sure you don’t do the math using average bitrate but peak bitrate. Slow and steady shots hold fewer bits than action-packed shots with a lot of movement. VBR uses a dynamic bitrate that changes during the recording, depending on the level of detail required to store. Variable bitrate is a bitrate control technique commonly used in video encoding to reduce file sizes. To be on the safe side, add 10-15% to your calculations so that you won’t run out of memory card space.
Instead, they publish approximate numbers. Three things to keep in mind when calculating video file sizes.Ĭamera manufacturers usually do not list exact bitrates. Some cameras display bitrates also in the settings menu.
CALCULATING MEGABITS PERSECOND MANUAL
The video bitrates for different codecs and picture settings are usually listed in the user manual and on the camera manufacturer’s website. Step two – divide card capacity with the file size of the 1-minute video: Step one – convert video file size from MB to GB: For this conversion, divide the video file size in megabytes by 1,024 since 1GB = 1,024MB.įor the 64GB memory card and the same 4K video that requires 2,100MB for one minute, the math goes as follows. Just don’t forget to convert the video file size from megabytes (MB) to gigabytes (GB) before you do that, as memory card capacities are usually given in gigabytes.
Simply divide the card capacity by the file size of the 1-minute clip, and voila – you have the answer. Once you know how much space a 1-minute clip takes up, it’s a no-brainer to figure out how many minutes can fit on a memory card. How many minutes of video can you fit on a memory card? So, a 1-minute 4K video, shot at 280Mbps, requires 2,100MB of memory card space. Step two – multiply the byte rate with the duration: Step one – convert bitrate into byte rate: For example, say you need to know how big is a 1-minute 4K video with a bitrate of 280Mbps. Then, multiply the byte rate with the duration of the video in seconds, and you get the file size in megabytes (MB). Video File Size = Bitrate (Mbps) / 8 (bits) x Duration (seconds)įirst, divide bitrate by 8 to get the byte rate. The Formula For Calculating Video File Sizes Our formula for calculating video file sizes already contains this step. Divide megabits by 8, and you get megabytes. Here’s all you need to know: 1 byte = 8 bits.ĭivide bits by 8, and you get bytes.
That conversion is easy to do yet equally easy to overlook, and this is why many people fail to do it. So, before all else, we have to convert the data rate from megabits per second (Mbps) into megabytes per second (MBps). The video bitrates are measured in bits but file sizes in bytes. Just multiply the bitrate with the duration of the video, and you’re done. Knowing that makes calculating video file sizes pretty straightforward. Video bitrate is usually measured in megabits per second (Mbps), so it tells you exactly how many bits are written to the memory card each second. The higher the bitrate, the higher the image quality. The bitrate (sometimes also called the data rate) refers to the amount of information a video carries per unit of time. Hence, all these aspects are automatically factored in when the formula contains bitrate. Whenever you go from 30fps to 120fps, bitrate changes. Put simply, things like the number of frames, colors, and pixels determine the video bitrate. You just don’t have to deal with them individually when you use bitrate for your calculations. Why codec, frame rate, and resolution don’t matter when calculating video file sizes?Ĭodec, compression, frame rate, resolution, color sampling, and color bit depth absolutely do matter, and they all significantly affect the video file size. Once you understand it, you can easily apply it to other file formats, including audio and still images. Plus, there is additional value in knowing why this formula works. However, if you want to know why this simple formula works or how it can be accurate without factoring in frame rate, resolution, and color depth, then take a couple of minutes and read this article.
CALCULATING MEGABITS PERSECOND FREE
Feel free to skip straight to the formula (below) and start punching in the numbers.
It literally takes less than ten seconds, and all the initial data you need is bitrate and duration. Despite all the different codecs and picture quality settings, calculating video file sizes is a quick and easy process.
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