Facebook limits the size of uploaded video files to 1024MB, which is 1GB. If your video is within the 20-minute time limit, but the file size is still too large, you can make some adjustments that reduce the amount of data stored in the video file. Use your favorite video compression software to tweak the bitrate, format, and resolution.

Adjust Bitrate

Bitrate represents the amount of data that can be processed in a specified amount of time. In video, bitrate is represented as kilobytes per second (kbps) for mobile video or megabytes per second (mbps) for standard formats. Higher bitrates mean a better quality image and audio, but also a larger file size. To estimate file size, you can add the video and audio bitrates in bytes per second (bit/s), and then multiply that number by the length of the video in seconds. To reduce the size of your video file, you can compress it to lower video and audio bitrates. For example, most high-definition video records at about 20 mbps with at least 128 kbps audio bitrate. If you do the math for a 60-second video, you find the file size is 1,200,768,000 bytes or about 1.2GB -- which exceeds the Facebook limitation. If you reduce the video bitrate to a Web-friendly 2 mbps and audio to 64 kbps, your end file size will be about 120 MB.

Reduce Resolution

Resolution represents the size of the video in terms of pixels wide and tall. The more pixels an image has, the sharper its image and larger its file size. Since the videos that display on Facebook can’t display any larger than 1,280 pixels tall or wide, you can compress your video to a smaller resolution to reduce file size. Just keep your resolution in the 16:9 if possible. In general, video intended for the Web can be published at least at a resolution of 710 x 400 for 16:9 ratio or 640 x 480 for 4:3 ratio.

Change the Format

Video format defines two things: the container, or type of file, and the codec used to compress the video data. A video file can be AVI (Audio Video Interleaved), MOV (QuickTime Movie), WMV (Windows Media Video), MP4, and other formats. Codecs include H.264, MPEG-4, VP8 and WMV. As an example, a MP4 video file can be compressed using MPEG-4 or H.264 encoding, among others. Facebook recommends using the H.264 codec for video with the AAC codec for audio in MOV or MP4 formats to create the best quality video at the smallest file size. You can convert your video to an appropriate format using your favorite video editing and publishing software.

Chunk It Up

If you aren't happy with the quality reduction from reducing the bitrates or resolution, you can try dividing your video into multiple clips. Use your favorite video editing software to create separate clips of your video, breaking the video in logical places. Try to keep your clips as even in length as possible, however, do not split your video in the middle of a thought or short process. If your video demonstrates a longer step-by-step process, you can use the end of a step as a split point. Ideally, you’ll find a spot that completes the first thought while compelling your audience to continue to the next clip.