Digital Audiovisual Properties
Basics

Peter Bubestinger-Steindl
(p.bubestinger@av-rd.com)

March 2019

Overview

  • Format naming
  • Image resolution
  • Framerate (fps)
  • Audio: Samplerate
  • Audio: Bit-depth

Video Formats

Which ones do you already know/use?

The "Trinity"

of digital video

Suffix = Container

Statements like "The videos are in Flash/AVI/MOV format" or "The camera creates MP4" usually only say something about the container format.

Why "Trinity"?

1 video file ≥ 3 formats.
Better would be to name all 3 components.

Better Naming Style

  • H.264 / AAC in MP4
  • XviD / MP3 in AVI
  • FFV1 / PCM in MKV

FourCC

"Is short for 'four character code' -
an identifier for a video codec, compression format, color or pixel format used in media files.

FourCC

FourCC

Examples

  • FFV1 = FFV1
  • v210 = V210
  • XviD = XVID
  • DV25 = DVCPro
  • DV50 = DVCPro 50
  • MJ2C, LCW2, LJ2K = MJPEG 2000
  • X264 = H.264
  • ...

Format Naming

Real-life Status Quo

Example "MPEG-4"

Source: The MPEG-4 Confusion

  • MPEG-4 video
  • MPEG-4 audio
  • .mp4
  • .m4v
  • .m4a
  • .m4p
  • MPEG-4 Flash video
  • MPEG-4 (AVI)
  • AAC / .aac
  • H.264
  • DivX
  • XviD
  • QuickTime
  • BluRay
  • Apple Lossless (ALAC/ALE)
  • MPEG-4 SP (Simple Profile)
  • MPEG-4 ASP (Advanced Simple Profile)
  • MPEG-4 SStP (Simple Studio Profile)
  • MPEG-4 AVC (Advanced Video Coding)
  • H.263
  • ...

Source: MAGIX product website (Feb.2015)

Source: MAGIX Produkt-Website (Okt.2016)

Image Resolution

  • = Width * Height
  • In Pixel (px)

Important Resolutions

Pixel Norm
720 x 486 NTSC SD
720 x 576 PAL SD
1280 x 720 HD-Ready
1920 x 1080 Full-HD
4096 x 2160 4k Digital Cinema

 

See also: Image Resolution (Wikipedia)

Per Video Format

Pixel Norm
500 x 480 Digital8
720 x 480 NTSC (DVD, miniDV, DigiBeta)
720 x 576 PAL DVD, miniDV, Digital8, DigiBeta
1280 x 720 HD DVD, Blu-ray, HDV
1440 x 1080 HDV (anamorph)
1920 x 1080 HDV, AVCHD, HD DVD, Blu-ray, HDCAM SR

Framerate

  • Images (=Frames) Per Second (FPS)

Framerates

  • PAL / SECAM: 25 fps
  • NTSC: 30000/1001 = ca. 29.97 fps

fps = AC frequency / 2

Thanks AEG for 50Hz! ;)

Variable Framerate

Variable Framerate

  • No constant image frequency
  • Each frame has individual display duration
  • Was rather uncommon...
  • ... but came back increasingly with mobile equipment.
  • Produces "unusual" frame rates when checking (because average)

Audio

  • Samplerate
  • Bits per sample (bit depth)
  • Channels

Samplerate

Bits per Sample

Hertz? kHz?

Samplerate is given as frequency:
Hertz (Hz) / Kilohertz (kHz)

Common Samplerate & Bits

Rate (Hz) Bits Application
11025 8
44100 16
48000 24
96000 32

Questions?

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