Encoders

TNT includes the best encoders for each use case.

Fraunhofer FDK AAC (Advanced Audio Coding)

  • Type/Purpose: Modern, high-performance audio encoder achieving great results even at low bitrates. It is a data compression method that can sound similar to a non-compressed file at high bitrates.
  • Encoders Available:
    • Fraunhofer FDK-AAC (all platforms): Industry-standard reference encoder, considered one of the best AAC encoders (with Apple's being arguably superior).
    • Apple AudioToolbox AAC (macOS only): Native, hardware-accelerated encoder optimized for Apple Silicon.
  • Bitrate Details:
    • Simple Mode: Set to 256 kbit/s, which gives very good results.
    • Maximum Bitrate: 512 kbit/s.
    • Quality Note: At 320 kbit/s, the encoder tends to lose almost all of its encoding artifacts.
  • Filesize Example: Thirty seconds of audio encoded with 256 kbit/s results in approximately 1 MB filesize.

Opus Interactive Audio Format

  • Type/Purpose: One of the newest audio encoders available. It's a modern data compression method that achieves very good results even with lower bitrates. It's an open-source format.
  • Best Suited For: Live applications due to its low algorithmic delay. It is also exceptionally great for human voice (radio, etc.) as it can be optimized for speech (utilized by TNT by a click of a button).
  • Bitrate Details:
    • Minimum Bitrate: 6 kbit/s (UI limits the minimum to 12 kbit/s).
    • Maximum Bitrate: 510 kbit/s.

FLAC (Free Lossless Audio Codec)

  • Type/Purpose: A lossless compression format that compresses audio without any quality loss, preserving the original audio data perfectly.
  • Ideal For: A wide range of applications such as archiving or digital delivery/fidelity when perfect audio fidelity is required.
  • Compression/Filesize: Reduces file size significantly (typically 40-60% of uncompressed PCM, depending on the compression level selected) while keeping the decompressed audio perfect. It is widely supported.

LAME / MPEG-I Layer 3 (MP3)

  • Type/Purpose: An older format, but one of the most compatible encoding formats available. Use this if the end-user may not be able to decode AAC or Opus.
  • Quality/Bitrate: It's not as capable at lower bitrates compared to AAC or Opus, but is usable at high bitrates (>320 kbit/s).
  • Filesize Example: Filesize for MP3 at 160 kbit/s for 30 second audio file is 0.6 MB.

PCM (Pulse Code Modulation) / WAV

  • Type/Purpose: Raw, uncompressed audio data (WAV is the container) used to digitally represent analog signals. It's the highest quality, but comes with the largest size cost.
  • Bitrate/Settings: This format does not have a single bitrate setting but is determined by two other settings:
    • Sample Rate: (e.g., 44.1, 48, 88.2, 96, 192 kHz) - Dictates how often the original data is converted into audio in a second (e.g., 48 kHz samples 48,000 times per second).
    • Bit Depth: (16, 24, 32, or 64) - Controls how precisely each sample is captured (32 and 64 are floating-point, used in specific scenarios).
  • Filesize Example: A thirty-second audio file with 48 kHz, 24-bit audio is 8.64 MB.

TNT Plus

Broadcast-quality audio normalization.

You could be interested in these support articles.

Processing

TNT is a powerful audio processing tool that lets you choose how you want your audio to sound.

Advanced mode

Advanced mode provides granular control over all encoding parameters.

You could be interested in these Guru articles.

Audio encoding artifacts

How audio encoders use psychoacoustic masking to reduce file sizes, and why this process creates audible artifacts in compressed formats.
Software
Outside broadcast without the truck.
Autonomous radio automation.
Broadcast-quality audio normalization.
Guru

Audio encoding artifacts

How audio encoders use psychoacoustic masking to reduce file sizes, and why this process creates audible artifacts in compressed formats.

Loudness and normalization

Understanding what is loudness, how it's measured and why standards exist.

Bit depth in digital audio

Understanding bit depth, quantization and why float sample rates are needed.

Audio dithering

How randomization helps to alleviate the effects of quantization.

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