Video Compression

What is Video Compression?

Video compression is the process of reducing a video's file size by encoding it more efficiently, usually by discarding detail viewers are unlikely to notice and avoiding repeated data between frames. It is performed by a codec (such as H.264, HEVC, ProRes or AV1) and controlled mainly by bitrate. Almost every video file you handle is compressed to some degree.

Why it matters

Uncompressed 4K video can exceed a gigabyte per second of footage, which is impossible to stream and impractical to send. Compression makes video usable. But every lossy encode removes information, and repeated encodes compound the damage. Filmmakers need to know when compression is helping (fast playback, manageable downloads) and when it is quietly degrading the film a client paid for, for example when a platform recompresses an upload or a client receives a preview file instead of the master.

How it works

Key concepts:

• Lossy vs lossless. Lossless compression keeps every bit; lossy compression discards data. Nearly all delivery codecs are lossy. ProRes and DNxHR are "visually lossless" at high data rates.

• Intra-frame vs inter-frame. Intra-frame codecs compress each frame on its own (good for editing). Inter-frame codecs like H.264 and HEVC store keyframes and then only the changes, which is far more efficient for viewing.

• Bitrate. The amount of data per second, in Mbps. Too low and you see blocking, banding and smeared motion, especially in dark scenes, grain, water or confetti.

• Chroma subsampling and bit depth. 4:2:0 8-bit is typical for delivery; 4:2:2 or 4:4:4 at 10-bit or more preserves color for grading.

• Generational loss. Each lossy re-encode adds artifacts. Always encode delivery files from the master, not from another compressed copy.

• Adaptive streaming. Streaming platforms encode several lower-bitrate versions and switch between them based on the viewer's connection.

Common approaches

Most platforms compress what you upload. YouTube and social networks re-encode aggressively for streaming. Vimeo also creates streaming versions, and depending on settings may offer the original for download. Google Drive and Dropbox store the original file but stream lower-quality previews. WeTransfer sends the file as-is. None of these is wrong; the important question is whether the client can get the untouched original when they need it, and whether the preview they watch is clearly a preview.

Does DLVRD compress my video?

No. DLVRD stores the file you upload exactly as exported and creates separate, optimized copies only for streaming in the gallery. When a client downloads, they receive your original file with the same codec, bitrate, color and metadata. This is why the stream and the download can look slightly different: the stream adapts to the viewer's connection, while the download is the master.