Bits per pixel
A bitrate on its own says nothing. 4 Mbps is lavish for 720p and starved for 4K60. Divide it by the pixels it has to cover each second and you get the one number that compares encodes across sizes and frame rates.
Frame size
1920×1080, 16:9. Pick Custom for anything else.
Codec
Bits per pixel is codec-neutral; the codec only moves where "typical" sits on the scale.
Bit density
- Frame
- 1920×1080 @ 30 fps
- Pixels per second
- 62.2 M
- Typical for H.264
- 0.088 (5.5 Mbps)
- This bitrate is
- 73% of typical
- Bits per pixel
- 0.064
Lean. Below typical. Fine for low-motion content; busy scenes will show it.
How to read it
Bits per pixel is bitrate ÷ (width × height × frames per
second): how many bits the encoder gets to spend on each pixel
of each frame. It is the density behind every bitrate table, and it
is why those tables are the shape they are. The scale under the
result places your figure against what published delivery ladders
spend at the same frame size, frame rate and codec: the same model the
bitrate calculator is built on, so the
two agree. "Typical" is 80% to 130% of that; "starved" is under half
of it, which is where blocking and smearing become the picture;
"generous" is over 1.3×, which is right for a master and wasteful for
a stream.
The bands are deliberately wide. Motion moves the right answer by a factor of two (a lecture at 0.04 bpp can look better than a football match at 0.12), and so does encoder effort. The reading is a sanity check, not a verdict: if a transcoding job comes back "starved", look at it before shipping it; if it comes back "generous", ask what the extra bits are buying.
Typical figures, for reference
H.264 delivery sits around 0.09 bits per pixel at 1080p30 and 0.07 at 4K30; HEVC and AV1 at roughly 60% and 50% of that. A Blu-ray at 25 Mbps for 1080p24 is about 0.5, which is the "generous" end made physical. Screen-share and webcam video in a conference call often runs under 0.03 and looks fine, because almost nothing in the frame changes between frames; the same density on a sports stream is unwatchable.