Video and audio editing

Welcome to the World of Multimedia Editing!

In this chapter, we are going to dive into the exciting world of video and audio editing. Whether you want to be the next big YouTuber, a film editor, or a music producer, understanding these basics is essential. Don't worry if you've never edited a clip before; we will break everything down into simple, bite-sized pieces. By the end of these notes, you’ll understand how professional-looking media is created and why certain technical choices are made.

Part 1: Video Editing – The Basics

Video editing is the process of manipulating and rearranging video shots to create a finished piece of work. It’s like putting together a digital jigsaw puzzle!

Fundamental Editing Techniques

1. Aspect Ratio: This is the relationship between the width and height of your video. Think of it like a picture frame. The most common one today is 16:9 (Widescreen), which is what you see on most TVs and laptops. Older TVs used 4:3 (more of a square shape).
2. Trimming: This means cutting off the "dead wood" at the start or end of a clip. Example: Trimming out the few seconds where you were walking toward the camera to press 'record'.
3. Splicing/Joining: This is simply taking two separate video clips and "gluing" them together so they play one after the other.

Adding Text and Information

To make a video professional, we need to communicate with the audience using text:
- Titles: Usually appear at the very beginning to tell the audience what the video is called.
- Subtitles: Text at the bottom of the screen that translates or repeats the spoken dialogue.
- Captions: Similar to subtitles but often include descriptions of sounds (e.g., [Ominous music playing]) to help people with hearing impairments.
- Credits: Found at the end. They list the people who worked on the video and where the music/images came from (source information).
- Scrolling Credits: These move up the screen. It is important to leave blank lines at the start and end so the names don't just "pop" in and out of existence!

Quick Review: Always ensure readability. Use high-contrast colors (like white text with a black outline) so your text doesn't disappear into the background.

Part 2: Visual Effects and Enhancements

Once the basic clips are joined, we add "flavor" to the video to make it more engaging.

Transitions and Movement

- Transitions: These are the effects used to move from one clip to the next. A Fade is a common transition where the image slowly disappears into a color (usually black).
- Pan and Zoom: If you have a still image in your video, you can use "Pan" to move the "camera eye" across it horizontally, or "Zoom" to move closer to a specific detail. This keeps the video feeling "alive" even when showing a photo.

Advanced Adjustments

- Filters and Colour Correction: Filters can change the mood (like making a scene look "warm" or "cold"). Colour correction ensures that the colors look natural and consistent across different clips.
- Speed Alteration: You can speed up a clip (time-lapse) or slow it down (slow-motion) for dramatic effect.
- Still Images: You can extract a single frame from a video to use as a photo, or insert an existing photo into your timeline. You may need to resize or crop these images so they fit the video's aspect ratio without leaving black bars on the sides.

Key Takeaway: Effects should enhance the story, not distract from it. Less is often more!

Part 3: Video Exporting and Compression

After editing, you need to turn your project into a file that others can watch. This is called exporting.

Common Video Formats

- MP4: The "king" of formats. It works on almost everything and provides good quality at a small size.
- AVI: High quality but files can be very large.
- MOV: Created by Apple; very common in professional editing.
- WMV: Created by Microsoft; primarily for Windows devices.

Understanding Compression

Raw video files are massive! Compression shrinks the file size. We compress video to different resolutions (the number of pixels on screen) depending on where it will be watched:
- Mobile devices: Lower resolution (saves data and battery).
- Internet/Streaming: Medium-to-high resolution.
- DVD/Blu-ray: High resolution for big screens.

Did you know? High compression makes a file small, but if you compress it too much, the video will look "blocky" or blurry. This is a trade-off between quality and file size.

Part 4: Audio Editing – The Basics

Sound is 50% of the movie experience! Audio editing involves cleaning up recordings and adding music or effects.

The Editing Process

1. Importing and Adding Tracks: You can bring in new sounds (music, sound effects) and layer them. You might have one track for the person talking and another for background music.
2. Normalising: This is a "quick fix" for volume. It adjusts the entire clip so the loudest part reaches a set level, making the whole thing easier to hear. It also helps in removing DC Offset (a technical error where the sound wave isn't centered correctly).
3. Trimming and Splicing: Just like video, you can cut out silences or "ums" and "ahs" and join different takes together.
4. Fading: Fade in starts quiet and gets louder; Fade out slowly disappears into silence.

Changing the Sound

- Pitch vs. Speed: Changing the speed makes the audio faster or slower. Changing the pitch makes a voice sound higher (like a chipmunk) or lower (like a giant) without necessarily changing the speed.
- Stereo to Mono: Stereo uses two channels (left and right ear), while Mono uses one. Sometimes we convert to Mono to save file space or if the recording was only made on one microphone.

Memory Aid: "Trim the fat, Join the chat." Trim to remove unwanted parts; Join (splice) to put the good parts together.

Part 5: Advanced Audio Effects

To make audio sound professional, editors use specific tools to "polish" the sound.

Filters and Enhancements

1. Equalisation (EQ): This allows you to adjust specific frequencies (bass, mid, treble).
- High Pass Filter: Lets High sounds through and cuts out low rumbling noises.
- Low Pass Filter: Lets Low sounds through and cuts out high-pitched hissing.
2. Noise Reduction: Helps remove constant background sounds like a buzzing fan or wind.
3. Delay and Echo: Adds a "repeat" to the sound. Reverberation (Reverb) makes it sound like the person is in a specific room, like a church or a small bathroom.
4. Overdubbing: This is recording a new layer of sound over an existing one. A voiceover is a classic example where a narrator speaks over background music.

Part 6: The Technical Side – Sampling and Formats

How does a computer actually "hear" sound? It takes thousands of "snapshots" of the sound wave every second. This is called Sampling.

Sampling Rate and Resolution

- Sampling Rate: How often the snapshots are taken (measured in Hertz, Hz). Higher rate = better quality but bigger file.
- Sampling Resolution: How detailed each snapshot is (measured in bits). Higher resolution = more accurate sound.

Audio Formats and Compression

Just like video, we have different "containers" for audio:
- WAV: High quality, uncompressed, very large files.
- MP3 / AAC / MP4a: Compressed files. They use Lossy compression, which means they throw away sounds the human ear can't easily hear to make the file much smaller.
- Lossless: Compression that shrinks the file without losing any data (like a ZIP file for music).

Quick Review Box:
- Higher Sampling Rate = Larger File + Better Quality.
- Lossy = Smaller File + Lower Quality (Data is deleted).
- Lossless = Larger File + Perfect Quality (Data is kept).

Summary – Bringing it all Together

Whether you are working with video or audio, the goal is always the same: to meet the needs of your audience.
- If you're making a video for a mobile phone user on a slow internet connection, you should use high compression and lower resolution.
- If you're making a professional film, you want the highest sampling rates and resolutions possible.
- Editing is about choices: balancing the quality of the media against the size of the file and how it will be delivered.

Don't worry if the technical terms like "DC Offset" or "Sampling Resolution" feel a bit heavy right now. Just remember that they are all just different ways to describe the "quality" and "size" of the digital files you create every day!