What are H.264 Compression Artifacts?

Balancing Bitrate and Video Quality with H.264 Compression

When using built-in H.264 compression on cameras, there is a trade-off between bitrate and video quality. The H.264 codec is highly efficient, allowing you to stream video at higher resolutions and lower bitrates. This efficiency is achieved by compressing video data, which can introduce some artifacts (commonly observed as "pixelation"), particularly during scenes with a lot of fast motion.

How H.264 Compression Works

H.264 compression is a widely used video compression standard that works by encoding video data in a way that reduces file size without significantly compromising quality. The codec achieves this by utilizing a combination of spatial and temporal compression techniques.

Spatial Compression: This method reduces redundancy within individual frames. It examines each frame and compresses areas that have similar colors and patterns.

Temporal Compression: This method takes advantage of similarities between consecutive frames. Instead of encoding each frame independently, H.264 records only the differences between a series of frames. This is particularly efficient for static or slow-moving scenes, but it can struggle with fast motion, leading to artifacts.

Understanding Artifacts in H.264 Compression

At extremely low bitrates of (1-5mbps), the H.264 compression algorithm prioritizes maintaining an overall smooth stream, which can result in artifacts such as blurring during rapid movement. This occurs because H.264 relies on predicting changes between frames, and fast motion creates significant differences that are challenging to compress effectively at lower bitrates.

The Benefits of H.264 Compression

Despite the potential for artifacts during high-motion scenes, H.264 offers significant advantages. It enables efficient streaming and storage of high-resolution video over limited bandwidth. This makes it feasible to transmit detailed underwater footage without requiring excessive data rates, which is crucial for remote monitoring and real-time applications.

For instance, using H.264 at a bitrate of 10-15mbps allows you to achieve a balance between video quality and bandwidth usage, making it suitable for a variety of underwater video applications.

~1 mbps Bitrate H.264 Video
~15 mbps Bitrate H.264 Video

Alternatives to H.264: Using MJPEG

If avoiding artifacts during high-motion scenes is essential, you might consider using MJPEG (Motion JPEG) compression. Unlike H.264, MJPEG compresses each frame as an independent JPEG image. This method eliminates motion-induced artifacts since each frame is processed individually, without relying on data from previous or subsequent frames.

However, MJPEG comes with a significant trade-off: it requires much higher bitrates to maintain similar video quality. MJPEG may need to operate at around 70mbps, resulting in much larger file sizes and higher bandwidth requirements. This can be impractical for many underwater applications where bandwidth is limited.

Managing Bitrate and Quality

To reduce artifacts in H.264 mode, consider increasing the bitrate. Allocating more data to each frame improves the codec's ability to handle fast motion, thereby reducing compression artifacts. 


Choosing between H.264 and MJPEG compression depends on your specific needs and constraints. If you prioritize smoother video with lower bandwidth usage, H.264 is a suitable choice. For example, with our Underwater USB Cameras, you can efficiently stream high-resolution video at manageable bitrates. However, if your priority is to avoid artifacts entirely and you can accommodate higher bandwidth and storage requirements, MJPEG may be the better option.

Understanding the trade-offs between different compression methods allows you to optimize the performance of your underwater USB camera, ensuring you get the best possible video quality for your specific application.

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