Understanding CODECs

Overview

This article aims to highlight the key differences between codecs. This article has been written to be easily digestible, and easy to search.

Common Codecs

These Codecs are commonly used by Crazytel.

PCMA | G.711a:

• A-law: A common audio coding standard used primarily in Europe and other parts of the world.
• High quality: Provides good audio quality but has a high bandwidth requirement (64 kbps).

Opus:

• Modern and versatile: A modern, flexible audio codec designed for a wide range of applications, including voice, music, and video conferencing.  
   
• High quality and efficiency: Offers excellent audio quality at various bitrates, making it suitable for different network conditions.

T.38:

• Fax over IP: Another standard for fax over IP, often considered more robust and reliable than H.232.

Uncommon Codecs

Although Crazytel won't block transmissions using these protocols, we don't recommend using them.

PCMU | G.711µ:

• µ-law: Another common audio coding standard, primarily used in North America and Japan.  
   
• High quality: Similar to PCMA in terms of audio quality and bandwidth usage.

G729:

• Low-bitrate: Designed for low-bandwidth networks, offering good voice quality at a much lower bitrate (8 kbps) than G.711.
• Popular for VoIP: Widely used in VoIP systems due to its efficient bandwidth usage.  
   

H.232:

• Fax over IP: A standard for transmitting fax signals over IP networks.
• Not an audio codec: Specifically designed for fax communication.