Video-Tech Glossary

Codec, Container, FPS, Bitrate & 17 Other Terms Explained in Plain English

“Wait - MP4 is what, exactly? A codec? A format? A sandwich?”
- Every bewildered newbie on r/VideoEditing

Jargon can turn even the most excited creator into a deer in headlights. This glossary fixes that. Skim the master table for a 60-second primer, then dive as deep as you like - each term comes with a definition, real-world context, and gotcha alerts you can act on today.

1. Master Table

(Bookmark this table or print the PDF cheat-sheet at the end.)

2. The Video Pipeline in a Nutshell

Sensor → Codec compresses frames → Container stores them → Editor/NLE tweaks → Export (new codec/bitrate) → Streaming protocol sends chunks → Player decodes → Display shows frames at set FPS and resolution.

Each glossary item sits at a different stage - understanding where unlocks better decisions.

3. Deep-Dive Definitions & Pro Tips

3.1 Codec

Definition (36 words)
A codec is a mathematical recipe that shrinks raw video/audio into manageable files and later reconstructs them for playback. “CoDec” = coder/decoder.

Why it matters
Wrong codec = upload failures, choppy editing, or massive files.

Pro tips / pitfalls

• H.264 is universal but 8-bit only - avoid for heavy color grading.
• AV1 saves up to 30 % bitrate vs. VP9 but needs beefy CPUs to encode.
• Never re-encode lossy→lossy more than once; quality snowballs downhill.

3.2 Container

Definition
A container is the lunchbox; it holds video, audio, captions, and metadata but does not define compression quality - that’s the codec inside.

Why it matters
Changing .mov to .mp4 doesn’t magically alter quality but can break players if streams aren’t supported.

Gotchas

• MP4 disallows some codecs (e.g., ProRes).
• MKV supports almost anything but confuses certain NLEs.

3.3 Frame Rate (FPS)

Frames per second determine motion smoothness and influence shutter speed choices on set.

• 24 fps → cinematic motion blur
• 30 fps → broadcast TV
• 60 fps → esports, slow-motion bases

Pitfall: Doubling FPS without doubling bitrate often results in half the per-frame quality.

3.4 Bitrate

Measured in Mbps (megabits/second). Higher numbers preserve detail but explode file sizes. Streaming services transcode towards efficient bitrates - beat them to the punch with smart settings (see 4 K/60 guide).

Rule of thumb: 1080p/30 SDR looks clean at 8 Mbps H.264, but 4 K/60 HDR may need 50 Mbps VP9.

3.5 Resolution

Pixels wide × tall. Upscaling 1080 p to 4 K rarely fools platforms into higher quality; they still judge bitrate & detail.

3.6 Aspect Ratio

16:9 dominates TVs; 9:16 rules mobile. Letterboxing wastes pixels - export native.

3.7 Bit Depth

8-bit offers 256 shades per channel; 10-bit jumps to 1 024, reducing banding in gradients.

Tip: Even if your camera shoots 10-bit, transcoding to 8-bit undoes the benefit.

3.8 Chroma Sub-sampling

Human eyes favor brightness detail over color. 4:2:0 stores one chroma sample for every four luma samples - great for distribution, bad for green-screen edges.

3.9 Color Space

Think of it as a paint palette. Rec. 709 = HD TV; Rec. 2020 = UHD/HDR. Feed a Rec. 2020 file to a Rec. 709 project without conversion and skin tones shift Martian.

3.10 HDR vs. SDR

HDR widens luminance (nits) and color. Requires 10-bit and metadata (PQ, HLG). Uploading HDR to a non-HDR pipeline leads to washed-out grays.

3.11 GOP / Key-Frame Interval

Long GOP saves bits; short GOP speeds seeking/editing. YouTube suggests ≤ 2 s between key-frames to limit cascaded re-compression.

3.12 VBR vs. CBR

• CBR (Constant) → predictable bandwidth, easy for live streams
• VBR (Variable) → adapts to complexity, smaller files
  Hybrid: YouTube accepts both; CBR 2 s GOP often safest.

3.13 Transcoding vs. Pass-Through

# Transcode H.264 → ProRes (quality-preserving, big file)
ffmpeg -i input.mp4 -c:v prores_ks -profile:v 3 -c:a copy prores.mov# Pass-through (no quality loss, lightning fast)
ffmpeg -i input.mp4 -c copy container_swap.mov

Every unnecessary transcode harms fidelity - copy streams if you only need a new wrapper.

3.14 Mezzanine Codec

Editing sweet-spot: visually lossless, intraframe, large. ProRes 422 HQ, DNxHR HQX, CineForm. Convert back to H.264/HEVC for delivery.

3.15 Streaming Protocol

HLS chops media into .ts chunks, DASH into .m4s. Both allow adaptive bitrate ladders - key for stutter-free playback.

3.16 Latency & Buffer

Live gamers chase <5 s glass-to-glass; corporate webinars can stomach 20 s for reliability. Buffer size trades delay for immunity to hiccups.

3.17 Variable Refresh Rate

Displays sync to source FPS, eliminating screen tearing - great for 48/50 fps regional content on 60 Hz panels.

3.18 Alpha Channel

Fourth channel (RGBA) stores transparency. Required for lower-thirds, logos, PNG sequences. Lossy codecs often discard it; choose ProRes 4444, VP9 lossless, or APNG.

4. FAQ Lightning Round

Q: Is MP4 a codec or container?
A: Container.

Q: Can I mix 60 fps and 24 fps clips on one timeline?
A: Yes, but your export FPS dictates motion cadence - choose wisely.

Q: Does higher bitrate always look better?
A: Only until you hit the codec’s perceptual transparency; beyond that you’re just inflating files.

Q: 4:4:4 vs. 4:2:0 - worth it?
A: Only if you’re keying, heavy grading, or archiving masters.

5. Quick-Reference Downloads

• Glossary Table PDF (print-friendly, 2 pages)
• SVG infographic of the video pipeline (inside the ZIP, 120 KB)

6. Further Reading

• MP4 vs. MOV: Keep Every Pixel Intact
• Optimal 4 K/60 fps Bitrates for YouTube: Field-Tested Guide
• Shrink Video by 70 % Without Looking Ugly: Compression Hacks

7. Share & Level-Up

If this glossary saved you a Google rabbit-hole (or three), bookmark it, send it to a confused colleague, and subscribe to our Frame-Perfect newsletter for monthly deep-dives - no spam, just clarity.