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Glossary · metric

What is Bitrate?

Bitrate is the amount of data a video or audio stream carries per second, measured in bits per second (bps) or kilobits (kbps) and megabits (Mbps). Higher bitrate means more detail per second of footage and a larger file. YouTube serves 1080p video around 4-6 Mbps and 4K around 15-25 Mbps.

Also called:kbps · mbps · data rate

Bitrate is the single most important number for predicting both file size and visual quality. A two-minute clip at 5 Mbps weighs 75 MB; at 25 Mbps it weighs 375 MB. For the same codec and resolution, doubling bitrate roughly doubles size and meaningfully improves quality.

There are two flavors. Constant bitrate (CBR) allocates the same number of bits to every second, regardless of how busy the picture is — so an empty static frame and a fast-cut chase scene get identical budgets. Variable bitrate (VBR) lets the encoder spend more bits on complex frames and fewer on simple ones, producing a noticeably better-looking file at the same average bitrate.

When a YouTube downloader advertises "1080p" without telling you the bitrate, assume it's the lower-bitrate VP9 variant rather than the higher-bitrate AV1 or H.264 streams. The pixel count is identical; the per-second detail isn't. VidPickr always saves the highest-bitrate stream YouTube serves for the resolution you pick — bytes are never re-encoded.

Common questions

What is a good bitrate for 1080p video?
For YouTube uploads, 8 Mbps is solid for SDR and 10-12 Mbps for HDR. YouTube re-encodes uploaded files, so the served stream is usually 4-6 Mbps for SDR 1080p — about half the recommended upload bitrate.
What's a good audio bitrate?
128 kbps AAC (m4a) is transparent for most listeners. 192 kbps is a comfortable margin for headphones. Above 256 kbps the gains stop being audible to almost everyone. Lossless formats (FLAC, ALAC) effectively bypass the bitrate question.
Does higher bitrate always mean better quality?
Within the same codec, yes. Across codecs, no — H.265 and AV1 produce equivalent quality at roughly half the bitrate of H.264 because they compress more efficiently.
Is bitrate the same as resolution?
No. Resolution is the pixel count (1920×1080); bitrate is how much data per second describes those pixels. A 1080p stream at 1 Mbps will look noticeably worse than a 720p stream at 5 Mbps — the lower-resolution one has more bits per pixel.

Related terms

Codec

A codec is the algorithm that encodes (compresses) and decodes raw audio or video into a smaller stream.

VBR (variable bitrate)

VBR (variable bitrate) is an encoding mode where the encoder spends more bits on complex frames and fewer on simple ones, instead of allocating the same budget to every second.

Resolution

Resolution is the pixel count of a video frame, expressed as width × height.

MP3

MP3 is the most widely supported audio format.

VidPickr is a free, browser-based YouTube downloader. Every term in this glossary either describes how YouTube delivers video or why your downloads behave the way they do. Try the downloader →