Video Bitrate
Estimate video bitrate based on resolution and codec
How to use Video Bitrate
- 1Enter the target file size and video duration.
- 2Enter the audio code rate to be deducted.
- 3Reads the video code rate required to reach the size target.
Invert video code rate by target size
Video-code rate = (Target bytes x 8/ time) - Audio-code rateIf the video has to be inserted into a fixed upload or storage budget, it can be extrapolated from size to size.
Leave a margin for the cost of the containment and audio; the calculator will first remove the audio and the video will receive the remainder.
Bitrate is the number of data per second of video, which directly determines the quality and volume of the painting. ** Code and resolution must match**: the same 8 Mbps to 1080p is clear, and 4K is a piece (because the pixel number is four times the pixel number, the data distributed to each pixel is only 1/4. Empirical law: 1080p about 8 Mbps, 4K about 35-45 Mbps is the starting point for "sufficient" and high dynamic content (sport events, video games) requires a higher number.
**The three control modes for the **code rate**: CBR (fixed rate, required for live broadcasting, of a predictable size but with the least painting efficiency), VBR (variable rate, recorded recommendation, complex scene automatic coding rate, best homogeneity) and CRF (consistent mass, x 264/x265 commonly used, you specify quality target 0-51, automatic codifier decision rate, ** CRF mode is most economical ** - values are lower in quality, 18 are near non-destructive, 23 are commonly used without loss of sight, 28 documents are significantly smaller but can see compression marks).
| Platform | 1080p | 1440p/2K | 4K | Encoder |
|---|---|---|---|---|
| YouTube | 8–12 Mbps | 16–24 Mbps | 35–45 Mbps | H.264 / VP9 |
| Bilibili | 6–8 Mbps | 12–16 Mbps | 20–30 Mbps | H.264 / HEVC |
| Dithered / TikTok | 4–8 Mbps | — | — | H.264 |
| Vimeo | 10–20 Mbps | 20–30 Mbps | 40–60 Mbps | H.264 |
| Twitch Live | 6 Mbps (ceiling) | — | — | H.264 |
| Netflix 4K | — | — | About 16 Mbps | AV1 / HEVC |
Recommended upload rate for mainstream platforms
Frequently asked questions
It's bigger than the target. Why?
Cover costs, key frames and audio take up additional space beyond the original video code rate.
The resolution or the code?
Decoding rate; loss of resolution permanently loss details.
What's the rate for an hour's video?
Videos are about 2.2 Mbps at approximately 128 kbps.
What about being re-compressed by the platform while uploading?
It's inevitable — all platforms are coded. What can be done is ** to feed the Platform to the highest quality of the source**: 1 upload at the upper limit of the Platform ' s recommended code rate (reserved for secondary compression); 2 using the Platform ' s preferred encoders and parameters (Youtube recommends H264 + high-code rate MP4); 3 resolution to keep the original (do not sample); and 4 to avoid material that has already been pressed many times. In addition, the platform allocates better coding resources to high-visibility videos (VP9/AV1 for YouTube) which is a long-term benefit.
What's the feed rate?
The live rate is subject to ** upper bandwidth** hard, not as high as possible. Empirical formula: live-live rate ≤ actually line bandwidth x 0.75 (25% residual for volatility and audio). 10 Mbps on top is measured with 6-7 Mbps. If the code rate exceeds the bandwidth, there will be a drop frame, a carton and a break. It is also important to consider the viewer end: the number is too high and the poor users of the network will remain buffered. ** It is proposed to open the dynamic code rate (the `dynamic code rate' of the OBS or the platform's self-adaptation stream) to allow the service to adjust automatically to the network. **