Always watch your video from start to finish after exporting before sending it on. This will give you the opportunity to make any necessary adjustments.
Exporting your file in full quality can sometimes reveal minor glitches that might go unnoticed when viewing the render files in your editing software.
Glitches can also sometimes arise during the export.
I'd also always choose the 'Export File' option in my editing software. This ensures you have a copy that you can distribute via whatever medium is needed as well as the original file as a backup for your records.
Exporting your file takes all of the information you've generated during your editing process, all the clip entry and exit points, references to original footage, layers, effects, text, audio, images, etc and compresses it down into a format that is smaller and easier to view and share.
Excess information is discarded and only the essential is kept.
The degree to which the video information compressed is determined by your choice of export settings.
Some video editors, rather than providing you with a choice of codecs, simply ask whether you want to export in a high, medium, low or custom quality setting.
Codec is short for compressor/decompressor and is a key factor in maintaining quality and optimising final file size. Below are a couple of common ones you may come across in your video editing software. The one I recommend for the majority of projects is H.264.
H.264 (AVC / MPEG-4) - Advanced Video Coding (AVC) is one of the most commonly used codecs and therefor one of the most compatible with video viewing and sharing programmes. The file size is small enough to share, but maintains a very acceptable quality.
H.265 (HEVC / MPEG-H) - High Efficiency Video Coding (HEVC) is the next incarnation of the previously established H.264. It reduces high resolution files even further to assist with storage and sharing, but because it is still relatively new, not all programmes can work with them yet.
ProRes (ProRes /422 / Proxy / LT / HQ / 4444 / 4444XQ) - Apple codec, very high quality large files. Use for storing footage you might like to edit again or for large scale cinema screenings.
Containers are digital file formats which hold together your video and audio elements in such a way that they can be played back synchronously. Some containers can also hold additional file information such as subtitles or metadata. Below are some common containers that you may find in your editing software. The one I recommend for the majority of video projects is .mp4.
.mp4 - One of the most universally compatible video formats, playable across most computer systems, video players and platforms.
.m4v - Apple equivalent of .mp4. Reduced file size. Most suitable for apple devices, but still has a reasonable degree of compatibility.
.mov - Designed by Apple for use with their Quicktime player. Most suitable for apple devices, but still has a reasonable degree of compatibility.
.wmv - Designed by windows for use with their Windows Media Player. Most suitable for windows devices. Limited compatibility with other computer systems and players.
.avi - Windows format, older version of .wmv. Larger file sizes. Limited compatibility, conversion would likely be required.
.avchd - Mainly a recording format rather than an export format, but you may come across it on Panasonic or Sony recording devices. Uses H.264 codec so is already keeping file sizes small during the recording process.
During your export process you may also be asked which resolution and frame rate you'd like to use for your final video.
Ideally you should choose the settings your video was recorded in as this will ensure the highest quality outcome.
If your project has involved multiple cameras on different settings or you have included external footage not shot by yourself, then I'd usually choose to export in the setting used the most across your footage.
If in any doubt, exporting in 1080 with a frame rate of 30 or 25 would be perfectly acceptable choice in the majority of cases.