> For the complete documentation index, see [llms.txt](https://library.zoom.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://library.zoom.com/admin-corner/network-management/quality-of-service-and-network-best-practices-explainer/how-zoom-audio-and-video-codecs-affect-bandwidth-usage.md).
# How Zoom Audio and Video Codecs Affect Bandwidth Usage
#### Zoom-enabled devices and Zoom products utilize proprietary codec technology to adapt to network conditions and CPU usage
Zoom’s Adaptive Codec at the application layer optimizes performance with what we call the “Reactive QoS Layer.” The Zoom application will adjust the video streams temporally (frames per second) and spatially (resolution).
{% hint style="success" %}
**Example**
If the Zoom Workplace desktop app is sending 720P resolution at 30 frames per second and the Reactive QOS layer detects that the CPU is highly utilized, the app will attempt to keep the same resolution but adjust to 15 frames per second to reduce the load on the CPU. If the Reactive QOS layer detects that the network I/O of the device itself is a bottleneck the Adaptive Codec will drop the resolution of all send/receive video streams to work within the available bandwidth. Taking these actions helps preserve audio for intelligible communication at low bandwidth.
{% endhint %}
#### Zoom uses industry-leading audio and video codecs to maintain high-quality media during varying network conditions and video layouts
The following table shows which audio and video software codecs are utilized by Zoom applications and Zoom-enabled devices.
{% hint style="info" %}
**Note**
The AV1 codec is only activated when: hardware encoding is **OFF** and your device is **not** in power-saving mode.
AV1 encoding is dynamically managed based on CPU load. Under high CPU conditions, the client will fall back to H.264 Advanced Video Coding (AVC) to preserve performance.
{% endhint %}
| Zoom Product | H.264 (AVC) | Opus audio codec | SILK audio codec | AV1 Codec |
| -------------------------- | ----------- | ---------------- | ---------------- | --------- |
| Zoom Workplace DesktopAapp | Yes | Yes | Yes | Yes |
| Zoom Workplace Mobile App | Yes | Yes | Yes | Yes |
| Zoom Workplace VDI App | Yes | Yes | Yes | Yes |
| Zoom Rooms | Yes | Yes | Yes | Yes |
| Zoom Phone | No | Yes | Yes | NA |
| Zoom Contact Center | Yes | Yes | Yes | NA |
#### The H.264 Scalable Video Codec adapts to video layouts, resolutions, and the video resolutions of other meeting participants
As more participants join a Zoom meeting, their Zoom applications will request certain video resolutions from the Zoom app that you are using. These requested resolutions will vary in quality based on the *remote* meeting participant’s selected video layouts. Your Zoom application can transmit up to four H.264 AVC video streams simultaneously to accommodate different resolutions requested by participants on the far end. The H.264 AVC also adapts to your video settings for content sharing and layout.
#### Opus and SILK codecs are used for audio communications in Zoom Meetings and Webinars and for Zoom Phone and Zoom Contact Center
SILK and Opus audio codecs are adaptive, dynamically adjusting their bitrates to real-time network conditions to provide the best voice communication quality. Recommended audio bandwidth allotments in this document are provided in ranges, given the dynamic function of these codecs
#### AV1 codec
AV1 (AOMedia Video 1) is an open video codec designed to provide high-quality video compression with greater efficiency than previous codecs. It enables high-quality video while reducing streaming and storage costs, offering significant reductions in file sizes without compromising quality. AV1 is optimized for high-resolution content and supports modern technologies like adaptive streaming and HDR content.
For more information, see the [Alliance for Open Media](https://aomedia.org/specifications/av1/) site.
---
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