VoIP has Worst Quality than Video App

Many users notice that VoIP calls sound worse than those from popular video conferencing tools such as Google Meet, Zoom, or Microsoft Teams. This difference is usually caused by the audio codecs and sampling rates used by the VOIP dialer or softphone.

Cause 1: Low-Fidelity Audio Codecs Used by Default

Many VOIP dialers use standard VoIP audio codecs by default. The most common ones are G.711 (8kHz sampling rate) for standard quality and G.729 (8kHz sampling rate) for lower bandwidth usage. These codecs are optimized for bandwidth efficiency and reliability, not for audio fidelity.

In comparison, most modern video conferencing applications use the Opus codec with sampling rates up to 48kHz, which preserves more audio detail and sounds more natural.

Solution 1: Use Higher Quality Codecs

Many modern VOIP softphones allow configuring a list of preferred codecs.

To improve audio quality, re-configure your VOIP softphone to use G.722 or Opus as the top default codec option, with a 16kHz or higher sampling rate.

When supported end-to-end (softphone, PBX, and SIP provider), this change can result in a noticeable improvement in the audio quality heard by the end customer.

Cause 2: Codec Negotiation Falling Back to Lower Quality

Even if higher quality codecs are enabled, the call may still fall back to a lower quality codec if any component in the call path does not support the preferred codec.

This includes the VOIP softphone, PBX, SBC, SIP trunk, or carrier.

Solution 2: Verify End-to-End Codec Support

Confirm that the selected codec (for example, G.722 or Opus) is supported and enabled on:

• The VOIP softphone
• The PBX or call manager
• The SIP trunk or carrier

If any device does not support the codec, the call may automatically downgrade to G.711 or G.729.

Cause 3: Softphone Codec Priority Order

Some VOIP softphones support multiple codecs but prioritize lower bandwidth codecs by default.

Solution 3: Adjust Codec Priority

In the softphone settings, move G.722 or Opus to the top of the codec priority list, and move G.711 and G.729 lower in the list.

Restart the communications application after making changes to ensure the new codec order is applied.

Learn More

To learn more about VOIP codecs and how they impact call quality, see this blog post.

If you are using Avaya, see this guide for configuration details.

If you are using Cisco, see this guide for configuration details.