Codec

A codec is not a container format — that's a common confusion. MP4 and MOV are containers; H.264 and ProRes are codecs that live inside them. Codecs split into two fundamental architectures: intra-frame and inter-frame. Intra-frame codecs (ProRes 422, ProRes 4444, DNxHR HQX, Apple ProRes RAW) compress each frame independently. Every frame is a self-contained I-frame. This means the decoder can jump to any frame instantly — critical for editing, where the NLE scrubs through footage randomly. ProRes 422 at 4K runs roughly 500–750 Mbps depending on content complexity; ProRes 4444 XQ can hit 1500 Mbps. These bitrates are massive but necessary for preserving chroma detail and latitude. Inter-frame codecs (H.264, H.265/HEVC, VP9, AV1) compress groups of pictures (GOPs). An I-frame is stored fully, then subsequent P-frames and B-frames store only the difference from reference frames. A Long-GOP structure might have an I-frame every 15–30 frames. This is incredibly efficient — H.265 can deliver visually similar quality at roughly 50% the bitrate of H.264 — but it's computationally expensive to decode for random access. Editing H.265 natively in Premiere Pro or Resolve will tax your CPU heavily, dropping playback frames on all but the most powerful machines. Then there's chroma subsampling. 4:4:4 preserves full color resolution — every pixel has its own unique chroma value. 4:2:2 halves horizontal chroma resolution. 4:2:0 quarters both horizontal and vertical chroma resolution. On a 3840x2160 frame, 4:2:0 means your color information is only 960x1080 — that's why green screen keys on 4:2:0 H.264 footage produce blocky, jagged edges around hair.

The acquisition codec vs delivery codec distinction is non-negotiable. Shoot on the highest-quality codec your camera and media support. On an ARRI Alexa, that's ARRIRAW at ~3.2 Gbps. On a Sony FX6, that's XAVC S-I (All-I, 4:2:2 10-bit at 600 Mbps) or RAW via Atomos. On a Canon R5, it's Canon RAW Light at ~1.5 Gbps. The 100 Mbps 4:2:0 8-bit H.264 that most mirrorless cameras default to is adequate for YouTube delivery but devastating for color grading — push the shadows more than a stop and you'll see banding, macroblocking, and color breaks that no amount of NR or secondary correction can fix. For delivery, H.265 at 15–30 Mbps is the sweet spot for streaming. Netflix mandates a minimum average bitrate of ~15 Mbps for 4K SDR content; Apple TV+ targets higher. But the encoding pass for delivery is a separate, final step — it should never be confused with the codec you edit and grade on. The professional pipeline is: shoot high-bitrate intra-frame or RAW, edit and grade on that (or optimized ProRes proxies), then encode to H.265/AV1 for distribution.