Compression without image degradation — every pixel remains identical after decompression. ProRes, DNxHD essential for grading and archival; higher file size but zero quality loss.
On set, you'll quickly notice the difference: lossless compression means that after decompression, the image data is pixel-perfectly identical to the original. Not a single value is discarded, no color channel is rounded. This isn't a luxury — it's a necessity if you want to work in editing or color correction later. H.264 compression would cost you too much detail, especially in the shadows and highlights where bits are already scarce.
ProRes and DNxHD are your standard codecs on set and in post. ProRes, in various quality levels (422, 422 HQ, 4444), gives you the flexibility to balance file size against a pure archival standard — 422 HQ is sufficient for most productions if you don't want your storage to explode. DNxHD works similarly reliably on Windows systems. Both work with 10-bit or 12-bit color depth, which is crucial for color grading: you can aggressively manipulate the midtones without creating banding.
The price is higher than with lossy codecs. A 4K minute of ProRes 422 HQ quickly eats up 8–10 GB of storage. With multiple cameras and multi-hour shooting days, you'll have to deal with SSD racks and redundant backups — not optional, mandatory. Additionally, your editing computer and your color suite need real hardware power. ProRes runs okay on a MacBook Pro, but with intensive grading involving multiple layers and effects, it gets tight.
There are also audio counterparts like FLAC, but that's rarely the main problem on a film set — your audio usually comes compressed or uncompressed directly from the mixer. When archiving masters (cinema DCPs, online masters), lossless compression is non-negotiable. The overhead is worth it: in five years, you'll still have exactly the data you need to re-grade or remaster. With lossy codecs, this option is gone — forever.