Video Streaming

What is Video Streaming?

Video streaming is the delivery of video over the internet in small pieces that play as they arrive, rather than requiring the whole file to download first. It relies on compressed renditions of the original, adaptive bitrate switching and content delivery networks to start playback quickly and keep it smooth. Streaming is about the technology that moves video to viewers; how the player looks and feels is a separate question of playback.

Why it matters

Your master file is rarely streamable as is. A 40 GB ProRes export or a 150 Mbps H.264 file would take minutes to buffer on a typical home connection, and would not play at all on many phones over mobile data. Streaming is what lets a client watch a large film instantly anywhere. Understanding how it works also explains why a stream can look slightly different from the master, and why that is normal.

How it works

A modern streaming pipeline has a few standard parts:

• Transcoding. The master is re-encoded into a "ladder" of renditions, for example 2160p, 1080p, 720p and 480p, each at a target bitrate. H.264 is the most compatible codec; HEVC, VP9 and AV1 are more efficient but less universally supported.

• Segmenting. Each rendition is cut into short chunks, usually 2 to 10 seconds, and described in a manifest using protocols such as HLS (common on Apple devices and the web) or MPEG-DASH.

• Adaptive bitrate (ABR). The player measures available bandwidth and buffer, then switches between renditions chunk by chunk. On a fast connection it climbs to the highest quality; on a weak one it steps down rather than stalling.

• CDN delivery. Segments are cached on servers around the world, so viewers fetch them from a nearby location.

Bandwidth is the main constraint. As a rough guide, 1080p streams need about 5 to 8 Mbps and 4K streams about 15 to 25 Mbps for good quality in H.264, less with more efficient codecs.

Progressive download vs adaptive streaming

Simpler setups use progressive download: the browser plays a single MP4 file as it downloads. With the "faststart" flag (moov atom at the front of the file), playback can begin almost immediately. It is simple and reliable but cannot adapt to changing bandwidth. Adaptive streaming is more complex to produce but handles mixed devices and connections much better, which is why large hosts like YouTube and Vimeo use it. Cloud drives tend to offer a single, heavily compressed preview, which explains why films can look soft there.

How does DLVRD handle video streaming?

DLVRD transcodes each upload into playback renditions that adapt to the viewer's device and connection, while your original file stays untouched for download. Playback copies are H.264 8-bit with faststart for broad compatibility.