Audio and video editing
FoundationFive steps: import, arrange the timeline, split and delete, add transitions/subtitles/audio, export; MP4 and 1080p cover everyday needs; keep music below the voice and mind copyright.
- Five steps: import, arrange, split and delete, add effects, export.
- Split is the basic cut for removing mid-clip silence.
- Consistent, simple transitions (fades) win; subtitles stay short and clear.
文體小知識：軟件操作課一步一步示範工具用法，例子可以直接在電腦上照住做，學完即刻用得到。
§Text Passage
1Video editing has five basic steps: import your material (clips, photos, music); arrange it in order on the timeline; trim the excess (split and delete); add transitions, subtitles and sound effects; export the finished file. A clear plan makes cutting fast.
2The most common cut is Split: move the playhead to the cut point, slice the clip in two, delete what you don't need. Transitions sit between clips so they join naturally — the plain fade is the safest; too many flashy transitions turn into clutter.
3Subtitles help viewers follow along and are essential where sound is off — many people scroll social media muted. For audio, keep background music quieter than the voice and fade it out at the end; always confirm the copyright of any music before using it — free-licence libraries are the safe choice.
4Exporting means choosing a format and resolution: MP4 is the universal video format that plays almost everywhere; 1080p (1920 × 1080) is plenty for everyday use, while 4K files are over four times larger and cost more to upload and store. Audio comes as MP3 (small) or WAV (uncompressed, high quality but large).
1Summary 重點摘要
Five steps: import, arrange the timeline, split and delete, add transitions/subtitles/audio, export; MP4 and 1080p cover everyday needs; keep music below the voice and mind copyright.
2Vocabulary cards Vocabulary
The editing workspace where clips are arranged in order and length.
Loading clips, photos and music into the project, usually via a media library.
Rendering the finished project into a video file, choosing format and resolution.
Cutting a clip in two at the playhead, so unwanted parts can be deleted.
An effect between clips that smooths the join, e.g. a fade.
Effects where picture or sound appears from nothing (in) or disappears to nothing (out).
Text overlaid on the picture to help viewers follow, essential when sound is muted.
The universal video format, supported by nearly every device and platform.
MP3 is a small lossy audio format; WAV is uncompressed, high quality but large.
3Step by step Steps
- Import the materialBefore editing begins, import all filmed clips, photos and music into the media library of the editing software, just as you would lay out your books before doing homework. For an open-day video, import the three interview clips and one music track at once, then rename them '01-gate', '02-lab' and '03-interview' so the assets stay organised. Tidy naming looks trivial but saves time later: files all called IMG_0001 force you to preview each one to find the right clip.
- Arrange the timelineThe timeline is the workspace where clips are laid out from left to right, and their order is the order the audience will watch. Arrange clips according to the storyboard: for an open-day video, gate welcome for 10 seconds, laboratory for 30 seconds, interview for 40 seconds and ending for 5 seconds, dragged onto the timeline one by one. Order controls rhythm and logic; opening with the interview leaves viewers confused because they have not yet been introduced to the school.
- Split and deleteSplitting cuts one clip into two so that an unwanted middle part can be removed. If the interview has 8 seconds of silence, place the playhead at the start of the silence and split, place it again at the end and split, select the middle piece and delete; the two remaining parts join automatically. A common beginner mistake is to split once and delete straight away, which removes everything after the silence as well — cut twice, select the middle, then delete.
- Add transitionsA transition sits where two clips meet and makes the join feel smooth. The safest choice is the plain fade: a 0.5-second fade between the gate and laboratory clips signals a change of scene without drawing attention. Keep one transition style throughout the whole film; beginners often pile up spins, page turns and flashes until viewers watch the effects instead of the content. Transitions are seasoning, not the dish itself.
- Add subtitlesSubtitles are the text lines at the bottom of the frame; they help viewers follow the content and are essential when people watch with the sound off, as many do on social media. Caption the interview line by line, keep each line within about 15 characters, show it for at least 2 seconds, and place it inside the lower safe area so platform buttons never cover it. Lines that are too long or flash past too quickly, or captions stuck to the very bottom edge, are the usual mistakes.
- Handle the audioAudio work aims to make every word audible. Keep background music below the voice, at about 30 percent of its volume, so it never drowns the narration, and add a 2-second fade at the end for a natural finish. Music of unknown origin — a file sent by a friend or downloaded at random — may belong to someone else, and publishing it risks copyright infringement; choose tracks from a free-licence library instead. Balance the levels first, then listen to the whole film once to confirm the sound is consistent.
- Export the resultExporting turns the timeline into a single video file. For homework, export as MP4 at 1080p; the 85-second open-day film comes to about 80 MB, and for social platforms 1080p is already sharp enough. Beginners assume a higher resolution is always better and force out a 4K file, which is over four times larger, uploads slowly, and looks no different on a phone screen. Decide the purpose and platform first, then pick the right export settings.
4Diagrams Diagrams
5Worked example Example
Example: three clips run 30 s, 45 s and 20 s; a 5-second silence is cut from the second clip, a 3-second title is added before the film, and a 2-second fade closes it. How long is the final cut?
- First add up the original total of the three clips: 30 + 45 + 20 = 95 seconds, the length before any editing.
- Cutting the 5-second silence from the second clip reduces the total to 95 − 5 = 90 seconds, which fixes the length of the film itself.
- The 3-second title goes before the film, so the total becomes 90 + 3 = 93 seconds; the 2-second fade is an effect occupying the final 2 seconds of picture and adds no length.
- Check with the other method: 30 + (45 − 5) + 20 = 90 seconds of film, plus the 3-second title = 93 seconds, agreeing with the first method and confirming the result.
- Answer: The final cut runs 93 seconds — 90 seconds of film plus the 3-second title; the fade is only an effect and adds no length. Add up all the clips first, then subtract what was cut and add the new title, and finally verify by calculating in a different order.
6Common mistakes Mistakes
7Quick check Quick check
Q1What is the basic operation for removing 8 silent seconds from the middle of a clip?
Q2Which export format is the most universal? A. MOV B. MP4 C. GIF
Q3What resolution is 1080p?
Q4How should background music be levelled in an interview video?
Q5What are two basic principles of subtitle design?
8Recap Recap
- Five steps: import, arrange, split and delete, add effects, export.
- Split is the basic cut for removing mid-clip silence.
- Consistent, simple transitions (fades) win; subtitles stay short and clear.
- Music sits below the voice; check copyright before using any track.
- Export MP4 at 1080p for everyday needs; 4K is heavy and costly.