File Formats

What are the 2 universal concepts behind all media formats?

Container (box)

Codec (recipe).

What’s the difference between Container and Codec?

Container = a file that holds media inside (like video, audio, subtitles)

Codec = shrinks vids into smaller sizes so they’re easier to stream or store.

JPG - when to use & why?

Smallest size

Lossy

Perfect for photos only

No transparency.

What does no transparency mean?

Image cannot show through to whatever is behind it - every pixel is fully opaque 

PNG - when to use & why?

100% quality

Lossless

Supports transparency → for logos/UI/assets.

WebP - why is it replacing JPG & PNG?

One format that can be lossy or lossless + transparency + animation → modern all-rounder.

Lossy Compression Definition

Throws away details permanently to make the file smaller.

Lossless Compression Definition

Keeps 100% of the original data, just packed more efficiently.

GIF - when is it a mistake to use?

Almost always - it’s ancient (256 colors) → only fine for tiny memes.

TIFF / RAW - what is their purpose?

Professional archival & editing

Never for delivery/web.

What does archival mean?

Archival = for long-term preservation, future - proof 

Not for sharing, not for web, not for everyday use.
You don’t care about file size - you care about zero quality loss.

SVG vs PNG - core difference?

SVG is math (scales forever)

PNG is pixels (can blur).

PDF - what makes it special?

Can contain vector + text + raster - print & document master format.

MP4 - why is it the default?

Maximum compatibility - safe everywhere.

What is a Raster Image?

An image made of fixed pixels. If you zoom in too much → it blurs.

Examples of Raster Image

JPG, PNG, WebP.

What is a Vector Image?

An image made of math instructions (like “Draw a circle at center x=50, y=50 with radius=25, color=#FF0000.”), not pixels.

Infinite resolution.

Examples of Vector Image

SVG, PDF, EPS

What Is Alpha Channel?

The extra layer in an image that controls transparency.
If a file has no alpha channel → it can’t be transparent.

Why do pirates love MKV?

Can hold ANY codec, multi-audio, subtitles, no limits.

What is MOV?

Apple’s version of MP4

Works best with iOS ecosystem.

What is WebM?

Google’s own modern video format

Specifically for the web and YouTube.

Why do Google and YouTube love WebM?

Open-source - anyone can use it for free
Royalty-free - no legal fees or licensing costs
Optimised for streaming - loads fast, low file size

When do you use raster vs vector?

Raster = photos.

Vector = logos/UI/illustration.

What are the 4 main codecs like people?

H.264 → The “default” guy

HEVC (H.265) → The “efficient upgrade”

AV1 → The “future king”

ProRes → The “professional filmmaker”

Tell me more about H.264. Why is the “default” guy?

• Used by YouTube, Netflix, TikTok - basically everything right now

• Works on every phone, laptop, TV

• Not the smallest file size, but 100% safe + compatible

How is HEVC (H.265) the “efficient upgrade”

• Same quality, but ~50% smaller file size than H.264

• Used for 4K on Netflix, iPhones, HDR video

• Not supported everywhere - some older devices choke

Why is AV1 the “future king”

• Even smaller files than HEVC

• Completely free to use (no licensing fees - big deal)

• YouTube, Netflix, TikTok are slowly switching to it right now

• Best if you want future-proof, efficient streaming

Why is ProRes the “professional filmmaker?'“

• Massive file size (like 50-100GB per movie)

• Used only for editing - NOT streaming or watching

• Apple created it for Final Cut Pro and Hollywood workflows

Why is H.264 everywhere?

Maximum compatibility - safe choice for any platform.

What is bitrate?

How much data per second a video uses - affects quality + file size.

More bits = more color shades = smoother, more realistic picture.

Unit for bitrate?

Mbps (megabits per second).

Higher bitrate means?

Better quality, larger file, more internet needed.

What is FPS?

Frames Per Second

Number of images shown per second

FPS - How smooth the motion feels 

24 fps is used for?

Movies / cinematic look.

60 fps is used for?

Smooth motion - gaming, sports, TikTok

Higher FPS = smoother motion,
but bigger file and sometimes looks “too real” for movies.

8-bit vs 10-bit - difference?

10-bit has FAR more colors → smoother gradients, no banding

What is SDR?

Standard brightness & color range - normal video.

What is HDR?

High Dynamic Range - brighter whites, deeper blacks, more realistic.