If you wish to record a live event, rather than stage something specifically for filming, it's as well to realise that you're at the mercy of circumstances. While all due care is taken, things beyond our control can disrupt things. Equipment can fail unexpectedly, many locations aren't very suitable for recording (poor power supplies, lighting, accoustics, etc.), and many performances are difficult to film (e.g. the audience and the cameras get in the way of each other).
Pre-production work is essential for good recordings, and is part of the overall production cost (we don't spend a couple of hours checking out locations, or watching rehearsals, before recording, for free). It makes the difference between a good job, and a bad job. Attempting to save costs by avoiding preparation work often costs you more, as increased post production time is needed to work around problems; as well as making productions look worse, because you often end up with problems that you can't cover up. Probably the worst pre-production omission is not bothering to obtain permission to film (from everyone being filmed, music being used, filming at the location, and bringing in equipment to film, etc.). All that time, money, and effort, is wasted if you can't use what you've produced.
Productions can be done in a variety of different ways. One of the best approaches to filming live events is to use multiple directed cameras that are mixed together on the location. All the shots are co-ordinated by a director, and they fit together. And the technical director ensures each camera is adjusted so that the technical differences between each camera's pictures are minimised. At the end of the shoot, the result is a video tape that's ready for presentation, with the minimum of post production being needed. Or, perhaps no post production needed, at all. Giving a rapid completion time to your job, which may be vital if you need to sell your video before the competition takes away all of your customers.
An alternative is to run multiple independent cameras, each videotaping separately, then editing together the results, afterwards. This suffers from not having a co-ordinated direction, the colours and exposures between the cameras mayn't match each other, and is very time consuming to post produce. It can easily cost more to spend a lot of time post producing, than all the costs of bringing in the equipment for a directed, mixed on the spot, shoot. Also, you can easily end up with sections where all the cameras produce something unusable, or identical to each other, with no alternative shots to fill in the space, simply because there isn't a director viewing the output from each camera, and co-ordinating what each cameraman does.
Taking the studio approach can be even better. Each event is tailored for being filmed, able to stop and restart as necessary, rather than trying to film an uninterrupted, long, production in front of an audience. Studio style production (whether done in an actual TV studio, or on location) can produce the exact look that you require, no matter how you actually had to go about filming it. Sections don't need to be shot in sequence, and can be ordered in the manner most convenient; although you have to be careful not to make mistakes which will only show up once you rearrange the shots into the correct sequence. Though studio productions can be more expensive, as people start to get really fussy about doing something special, and spend too much time producing each scene.
Probably the worst approach is using a single camera. If there's a filming problem you have no alternative shot. Everything is shown from a single viewpoint, unless you move the camera around. If you do move the camera, you either see it moving about (which can be difficult to do smoothly), or you miss out on things while the camera is relocated. That doesn't work well for live performances, with important things being missed, and jumps in the sound track. Single camera productions are really only suitable for things like corporate videos, where you're not recording a “live event.” Or where you're just recording an event for a record of what happened, no matter how boring the video turns out.
With particular emphasis on the last approach, it's almost impossible to produce something without some editing. Editing in the camera just doesn't work. It takes time for a camera to start recording, so you start recording before the action commences. This means that things are recorded that you don't want on the final tape. Trying to edit in the camera, by anticipating when to start and stop, nearly always means that you'll miss the start of something (and more than just a couple of seconds, perhaps a minute or more), or you'll stop recording before it really finishes. And you nearly always need to remix the sound. As a bare-minimum approach, this is what's usually needed:
Good information about what is going to be recorded, and about the location.
Some modification of the activity so that it can be successfully recorded (lighting, sound, cues to co-ordinate filming and action, etc.).
Theatre lighting is, quite often, completely inappropriately set up for video recording. We find we keep on having to deal with: An inadequate amount of light, overall (either they simply don't have enough lighting, or they're deliberately running it too dimly). Very uneven lighting levels across the stage (dim in places, and very over-lit in others) where it's all supposed to be consistent, making it impossible to get a decent shot that covers a wide area. Colour changes across the stage where it wasn't intentional. Lighting will need to be set while the scene is observed with a camera, or you'll just have to put up with bad looking video.
The techniques of mixing sound for recording purposes versus sound re-inforcement (amplifying live sounds) are different, and not always compatible. It isn't always feasible to take a feed from the mixing desk, when it's being mixed for sound re-inforcement. We usually get better results by miking the room, and mixing things ourselves. And if you're doing a performance just for recording purposes, you can often get much better sound without additional amplification (i.e. turn off the amplifiers, or turn them down). I find that sound re-inforcement is typically done in a manner that makes things sound shrill and tinny, or the complete opposite (way too much bass), is usually amplified far in excess of what's needed, and doesn't usually mike up everything that needs to be recorded. Sometimes, maybe even often, amplification is completely un-needed, and things sound much better without it.
Equipment set up time (anything from half an hour, to four hours, depending on the job).
Filming of the event, and perhaps filming of some additional material for editing purposes.
Equipment pack up time. No, we don't pack up in a hurry and then sort the mess out later, in our own time.
Minimal editing of recording to remove extraneous material, to cover up problems experienced while filming, to add titles, and to adjust sound levels; all to produce a master tape that can be simply duplicated with no more tweaking required.
If all goes well, this will take about two to three times the length of the final product. You have to check the material before editing (to find the best and worst bits), edit the material in sections, and check how each edit went.
Generation of client copies (e.g. recording onto VHS or DVD). This is done in real time (a one hour recording takes an hour to duplicate, plus a bit of time to handle the tapes or discs in and out of the machines, labelling, etc.).
A simple single-camera job of recording a seminar might involve half an hour of setting up (putting a microphone somewhere useful, running cables around), video taping for an hour, half an hour of packing up, two to three hours of editing (assuming that the filming went without any hitches), then about an hour of dubbing (more for multiple copies, of course). With expenses of one camera tape, one editing tape, and whatever tapes or discs were used for the dubs.
A more complex multi-camera production would probably involve some consultation about what was going to occur, what equipment would be needed for it, some re-organisation or arranging good co-ordination of activities for successful filming, a visit to the location (before the recording date), a few hours of setting up (bringing in equipment, running cables around, getting good sound and lighting organised), a “practice run” filming a performance (so all of the crew is aware of what's going to happen, and decisions can be made about how to do it best), filming another performance (aimed at being the taped version, though several performances could be edited together as if they were just one), an hour or more of packing up, some editing to add in titles and tidy up the beginnings, endings, any breaks in between, and perhaps compile several performances into one (again, the editing probably taking two to three times the length of the performance running time, assuming that everything went smoothly), then dubs of the finished edit.
It should be noted that no matter what filming approach is taken, it's difficult to estimate how much editing time will be needed. Especially if there were problems during filming, the filming had to be done in a complex manner, or complex requirements were made for the end result. For some jobs similar to the examples I've outlined, but involving modest complexities, you should probably budget for half a day of filming, and for half to a full day of editing. Though if you're not getting me to organise the production and the editing, you should probably budget for several days of editing. That's been my experience of comparing how I work, to how other people complete the same tasks.