Optimal HEVC Compression for Equivalent AVC Quality with Minimal Storage

When considering video compression for web and various digital platforms, one frequently debated concept is the optimal compression settings for High Efficiency Video Coding (HEVC, H.265) to match the quality of an Advanced Video Coding (AVC, H.264) video while minimizing storage usage.

Bitrate Comparison and HEVC Efficiency

HEVC is designed to be more efficient than AVC, achieving similar quality at approximately 50% of the bitrate. For instance, if an AVC video has a bitrate of 8 Mbps, the equivalent HEVC video might only need around 4 Mbps to maintain the same quality. This efficiency is crucial for minimizing storage requirements and improving streaming performance without compromising on visual quality.

Calculating Storage Usage: To calculate the storage size for a video, use the formula: Size Bitrate (Mbps) × Duration (seconds) / 8. For example:

AVC video at 8 Mbps for 10 minutes (600 seconds): Size 8 Mbps × 600 seconds / 8 600 MB HEVC video at 4 Mbps for the same duration: Size 4 Mbps × 600 seconds / 8 300 MB

Factors Affecting Compression

Different video content types and resolutions play significant roles in how HEVC compresses. Understanding these factors ensures optimal settings for encoding.

Factors Influencing HEVC Compression:

Content Type: Fast action scenes or complex scenes may require higher bitrates to maintain quality. Static scenes, on the other hand, can be compressed more efficiently. Resolution: Higher resolutions like 4K benefit significantly from HEVC's efficiency, whereas lower resolutions like 1080p might see less improvement. Target Quality: Define the target quality using tools like PSNR (Peak Signal-to-Noise Ratio), SSIM (Structural SIMilarity index), or subjective viewing tests to determine appropriate settings.

Recommended Settings for HEVC Encoding

To optimize HEVC encoding, consider the following settings:

Profile: Use Main or Main10 profile for a good balance between compression efficiency and compatibility. Preset: Utilize slower presets like slow or veryslow in encoders like x265 to achieve better compression efficiency. Tune: Use tuning options based on the video's content, such as film, animation, etc., to further optimize results.

Performance Comparison

The optimal compression for an HEVC video to achieve the same quality as an AVC video with minimal storage can be calculated. For instance:

HEVC: 11.5 Mbps of bitrate per 1.25 Mbps per frame 1 GB per minute AVC: 4 Mbps of bitrate per 8 Mbps per frame 2 GB per minute

This data demonstrates the significant storage reduction achieved through HEVC encoding.

Conclusion

In summary, to achieve the same quality as an AVC video while minimizing storage, encode the video in HEVC at approximately 50% of the AVC bitrate. Adjust encoding settings based on the video's content and desired quality to optimize the results further. By understanding the factors affecting HEVC compression and implementing the recommended settings, you can achieve effective and efficient video compression.