IPTV Glossary: Understanding Bitrate, Codec & Transcoding

Our main IPTV glossary defines bitrate, transcoding and similar terms in one line each. This page goes one level deeper into how those three interact to set picture quality, which helps once you're troubleshooting a specific quality problem.

Bitrate, in practice

Bitrate is measured in Mbps and roughly tracks with resolution: standard-definition streams typically run 1-3 Mbps, HD around 5-8 Mbps, and 4K commonly 25 Mbps or more, depending on the codec. Two streams at the same resolution can still look different if one runs a noticeably higher bitrate. More data per second means fewer compression artifacts, but it needs more sustained bandwidth to avoid buffering.

Codec: why bitrate numbers aren't directly comparable

The codec is the compression algorithm doing the encoding, and it changes what a given bitrate can deliver. Newer codecs like H.265/HEVC squeeze noticeably more picture quality out of the same bitrate than older standards like H.264, so a 4K stream in HEVC can look as good as an H.264 stream at a much higher bitrate. That efficiency gain is also why device decode support (see 4K requirements) matters: older hardware often can't decode HEVC at all, forcing a fallback to a less efficient codec.

Transcoding: where the two meet

Transcoding is the server converting a stream's format, resolution or bitrate on the fly. It usually adapts one source stream for different devices and connection speeds, so the server doesn't have to store a copy for every combination. It trades source quality against what each viewer's connection and device can handle.

Why these terms matter

They help when troubleshooting picture quality. See why picture quality sometimes drops for the practical application.