When exporting your video, what is the key difference between using a common codec like H.264 versus a newer one like H.265 regarding file size and quality?

When exporting video, a codec is a technology used to compress and decompress digital video data, reducing its file size for storage and transmission while aiming to preserve visual quality. The key difference between H.264 and H.265 lies in their compression efficiency, which directly impacts the relationship between file size and quality.

H.264, also known as Advanced Video Coding (AVC), is a widely adopted and mature video compression standard. It achieves good compression by identifying and removing redundant information within video frames and between successive frames. When exporting with H.264, you can achieve a balance of quality and file size that is broadly compatible across most devices and platforms due to its long-standing use.

H.265, known as High Efficiency Video Coding (HEVC), is a newer compression standard designed to be significantly more efficient than H.264. Its primary advantage is superior compression efficiency, meaning it can achieve the same perceptual video quality as H.264 at a considerably smaller file size. This is accomplished through more advanced algorithms, such as larger and more flexible coding blocks (called Coding Tree Units or CTUs), improved motion prediction, and enhanced entropy coding, which more effectively identifies and discards redundant data. For example, H.265 can typically deliver the same visual quality as H.264 with a file size reduction of approximately 25% to 50%, depending on the content and encoding settings.

Conversely, if you export a video using H.265 at the same target file size as an H.264 video, the H.265 version will exhibit a noticeably higher visual quality. This is because H.265's more efficient algorithms allow it to retain more detail and reduce compression artifacts within the same data budget. Therefore, the key difference is that H.265 provides a more favorable trade-off: either significantly smaller file sizes for comparable quality or higher quality for comparable file sizes, compared to H.264.