CEA Broadcast Audio and Streaming Standards

Question 1

What loudness standard does the ATSC A/85 specification mandate for US broadcast television?

Accepted Answer

-24 LKFS

Answer

-23 LUFS

Answer

-16 LUFS

Answer

-14 LUFS

Question 2

What audio codec is widely used for digital broadcast audio in the US ATSC standard?

Accepted Answer

Dolby AC-3 (Dolby Digital)

Answer

MP3 (MPEG-1 Audio Layer III)

Answer

AAC (Advanced Audio Coding)

Answer

Opus

Question 3

What is the function of 'dialog normalization' (dialnorm) metadata in Dolby AC-3/Dolby Digital broadcast streams?

Accepted Answer

It specifies the average loudness of dialogue in the program, allowing decoders to adjust playback level to a target reference, ensuring consistent perceived loudness between programs

Answer

It applies automatic gain control to dialogue channels independent of music and effects levels

Answer

It sets the minimum loudness floor below which the decoder will not reduce program level

Answer

It adjusts the center channel delay to align dialogue with lip movements on screen

Question 4

What is the purpose of 'audio description' (AD) in broadcast audio?

Accepted Answer

A narrated commentary track added to a broadcast describing visual elements of a program for blind and visually impaired viewers

Answer

An embedded metadata track that describes the audio codec and channel configuration of a broadcast stream

Answer

A closed-caption format specifically designed for audio-only radio broadcasts

Answer

A stereo downmix algorithm used when 5.1 broadcasts are played on 2-channel TVs

Question 5

What sample rate and bit depth are standard for professional broadcast audio in television production?

Accepted Answer

48 kHz / 24-bit

Answer

44.1 kHz / 16-bit

Answer

96 kHz / 32-bit float

Answer

32 kHz / 20-bit

Question 6

What does 'SDI embedded audio' allow in a broadcast facility?

Accepted Answer

Up to 16 channels of uncompressed PCM audio carried within the same Serial Digital Interface (SDI) coaxial cable as the video signal

Answer

Distribution of audio as a separate AES3 digital signal alongside the video feed

Answer

Wireless transmission of broadcast audio using SDI modulation over RF

Answer

Storage of audio metadata in the VANC (Vertical Ancillary) lines of the SDI signal only