Compression that discards unrecoverable image data — H.264, H.265. Saves storage but degrades quality permanently. Unsuitable for masters; fine for proxies.
When shooting in 4K or higher, you quickly reach the limits of storage capacity. Lossy compression is the pragmatic compromise: specific image information is discarded that the human eye doesn't perceive anyway—or only under certain conditions. H.264 and H.265 work on this principle. They analyze each frame, identify redundant data (spatial and temporal redundancy), and remove it. This dramatically saves storage—an hour of 4K footage shrinks from several hundred gigabytes to a manageable size. The price: this information is gone. It cannot be recovered.
On set, this is often the only option. An 8K camera like the RED KOMODO records internally with H.265—not for the fun of compression, but because uncompressed, the data rate would be physically impossible to handle. The same applies to broadcast cameras or drones. You have to be aware: the more aggressive the compression (the lower the bitrate), the more visible artifacts appear—blocking in dark areas, color fringing at edges, motion blur that doesn't come from the lens. This will become visible later in the grading suite, especially when increasing contrast or performing aggressive color corrections.
The crucial difference to lossless compression (like ProRes or DNG sequences): there, all pixel information is retained; the original is reconstructed 100 percent. Lossy means: once compressed, always compressed. Multiple renders with H.264 or H.265 exponentially worsen the artifacts—which is why editors work with mezzanine formats and only encode for delivery at the very end.
Practical tip: When recording with H.265, choose a higher bitrate than necessary—100 Mbps instead of 50 Mbps for 4K saves 50 percent storage compared to ProRes and delivers significantly cleaner material. For long-term archiving and premium projects: unacceptable. For documentaries, corporate productions, streaming preparation: perfectly viable. The technology is mature—but it's a one-way ticket. Anyone who later needs higher-resolution material or plans extreme grades should factor this in from the start.