Video Production Formulas

Updated

Formulas for encoding and delivery: file sizes and compression ratios, streaming bitrates and ladders, resolution, audio size, sync and loudness, render and upload times.

25 min readIntermediate
  • Video Production
  • Technical Formulas
  • Streaming & Encoding
  • Workflow Optimization
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Introduction to Video Production Math

The formulas behind encoding and delivery: file sizes and compression ratios, streaming bitrates and ladders, resolution, audio sizes and loudness targets, and the time it takes to move and render it all. For step-by-step walkthroughs, see the guides to bitrate and storage planning.

1. Compression Ratios & File Sizes

File size is bitrate × duration. Work out the uncompressed size from the frame dimensions, bit depth and chroma subsampling, and the compression ratio tells you how much a codec saves. The free bitrate calculator turns bitrate and runtime into file size in your browser.

Compression Ratio Formula
Compression Ratio = Uncompressed Size ÷ Compressed Size

How many times smaller the compressed file is than the uncompressed original.

Where

Uncompressed Size
Original file size before compression(GB)
Compressed Size
Final file size after compression(GB)

Example: ProRes 422 vs Uncompressed 4K UHD (24fps, 1 hour)

Calculation:
2,687 GB ÷ 212 GB ≈ 12.7
Result:
About 12.7:1 compression ratio
Uncompressed Video File Size
File Size (GB) = (Width × Height × Frame Rate × Duration × Bit Depth × 3) ÷ (8 × 1,000,000,000)

The size of uncompressed video with three full-resolution color channels (RGB or 4:4:4). For subsampled video, replace the 3 with the multiplier below.

Where

Width × Height
Resolution in pixels(pixels)
Frame Rate
Frames per second(fps)
Duration
Length of video(seconds)
Bit Depth
Color depth per channel(bits)

Example: 4K UHD, 24fps, 10-bit, 1 hour

Calculation:
(3840 × 2160 × 24 × 3600 × 10 × 3) ÷ (8 × 1,000,000,000)
Result:
≈ 2,687 GB uncompressed
Compressed Video File Size
File Size (MB) = (Bitrate in Mbps × Duration in seconds) ÷ 8

For any compressed file: bitrate × time. Use the total bitrate, video plus audio.

Where

Bitrate
Video bitrate(Mbps)
Duration
Length of video(seconds)

Example: 50 Mbps H.264, 1 hour duration

Calculation:
(50 × 3600) ÷ 8 = 22,500 MB
Result:
22.5 GB file size

Storage Requirements Table

ResolutionUncompressed 10-bit RGB (1 hour)H.264 (50 Mbps)
1080p (24fps)672 GB22.5 GB
4K UHD (24fps)2.69 TB22.5 GB
8K UHD (24fps)10.7 TB22.5 GB

2. Streaming Bitrates & Quality

Streaming bitrates are a trade between picture quality and the bandwidth viewers actually have. A bits-per-pixel figure gives a first estimate; published ladders and test encodes refine it.

Bitrate from Bits per Pixel
Bitrate (Mbps) = (Width × Height × Frame Rate × Bits per Pixel) ÷ 1,000,000

A rule of thumb for a starting bitrate. Grain, noise and fast motion need more; clean, static images need less.

Where

Width × Height
Resolution in pixels(pixels)
Frame Rate
Frames per second(fps)
Bits per Pixel
Quality factor, typically 0.05-0.2(bits)

Example: 4K UHD at 24fps, high quality

Calculation:
(3840 × 2160 × 24 × 0.1) ÷ 1,000,000 = 19.9
Result:
About 20 Mbps as a starting point
Buffer Size
Buffer Size (Mb) = Bitrate (Mbps) × Buffer Duration (seconds)

How much data a player has to hold to cover a given number of seconds of playback. Divide by 8 for megabytes.

Where

Target Bitrate
Video bitrate(Mbps)
Buffer Duration
Buffer length (typically 2-10 seconds)(seconds)

Example: 25 Mbps stream with 5-second buffer

Calculation:
25 × 5 = 125 Mb; 125 ÷ 8 = 15.6 MB
Result:
125 megabits (about 15.6 MB) of buffer
Adaptive Bitrate Ladder
Next Bitrate = Previous Bitrate × Step Factor

An adaptive stream offers the same video at several bitrates, and the player switches between them. Apple's example ladder for HLS steps up by about 1.3 to 2.5 times per rung.

Where

Previous Bitrate
Lower quality bitrate(Mbps)
Step Factor
Typically 1.3-2.5(multiplier)

Example: Building up from 2 Mbps with a factor of 1.5

Calculation:
2 → 3 → 4.5 → 6.75 → 10.1 Mbps
Result:
A 5-rung ladder

Example Streaming Bitrates (Apple HLS Ladder)

Average bitrates from the 16:9 example ladder in Apple'sHLS Authoring Specification, for SDR content up to 30fps. Apple lists two rungs at most resolutions and no H.264 rung above 1080p. It suggests about 20% less for 24fps HEVC.

ResolutionH.264HEVC (H.265)
720p3 and 4.5 Mbps2.4 and 3.4 Mbps
1080p6 and 7.8 Mbps4.5 and 5.8 Mbps
1440p—8.1 Mbps
2160p (4K UHD)—11.6 and 16.8 Mbps

3. Resolution Scaling & Aspect Ratios

How far a frame is scaled, and how many pixels each delivery resolution holds.

Scaling Factor Calculation
Scaling Factor = Target Resolution ÷ Source Resolution

Calculate the scaling factor when changing resolutions.

Where

Target Resolution
Desired output resolution(pixels)
Source Resolution
Original input resolution(pixels)

Example: 4K to 1080p downscale

Calculation:
1920 ÷ 3840 = 0.5
Result:
0.5x scaling factor (50% size)
Pixel Count Calculation
Total Pixels = Width × Height

Calculate total pixel count for resolution comparisons.

Where

Width
Horizontal resolution(pixels)
Height
Vertical resolution(pixels)

Example: 4K UHD resolution

Calculation:
3840 × 2160 = 8,294,400
Result:
≈ 8.3 megapixels

Common Resolution Standards

StandardResolutionAspect RatioTotal Pixels
HD1920×108016:92,073,600
4K UHD3840×216016:98,294,400
8K UHD7680×432016:933,177,600

4. Audio Production Calculations

Uncompressed audio size, sync offsets and the loudness targets your mix will be measured against. The audio sample rates guide explains why video sound is 48 kHz and how many samples fall in each frame.

Audio File Size
File Size (MB) = (Sample Rate × Bit Depth × Channels × Duration) ÷ (8 × 1,000,000)

The size of uncompressed PCM audio, such as WAV or BWF, ignoring the small file header.

Where

Sample Rate
Audio sampling frequency(Hz)
Bit Depth
Audio bit depth(bits)
Channels
Number of audio channels(count)
Duration
Length of audio(seconds)

Example: 48kHz, 24-bit stereo, 1 hour

Calculation:
(48,000 × 24 × 2 × 3600) ÷ (8 × 1,000,000) = 1,036.8
Result:
About 1,037 MB (1.04 GB) per hour of stereo
Audio Sync Offset
Offset (ms) = (Video Frame ÷ Frame Rate − Audio Sample ÷ Sample Rate) × 1000

Convert the sync point in picture and in sound to seconds and subtract. A negative result means the sound is late, so slide it earlier by that amount.

Where

Video Frame
Frame where the slate closes(frame)
Audio Sample
Sample where the clap is heard(sample)
Frame Rate
Video frame rate(fps)
Sample Rate
Audio sampling frequency(Hz)

Example: Slate closes on frame 240 (24fps); clap heard at sample 482,000 (48kHz)

Calculation:
(240 ÷ 24 − 482,000 ÷ 48,000) × 1000 = (10 − 10.0417) × 1000
Result:
−41.7ms: the sound is one frame late, so move it 2,000 samples earlier

Common Audio Specifications

FormatSample RateBit DepthUse Case
CD Quality44.1 kHz16-bitConsumer
Professional48 kHz24-bitFilm/TV
High-Resolution96 kHz24-bitStudio

5. Workflow Planning & Optimization

Render, storage and upload estimates for scheduling a job. The free upload time calculator gives a best-to-worst upload range in your browser.

Render Time Estimation
Render Time = Timeline Duration × (Test Render Time ÷ Test Section Length)

Render speed depends on the codec, effects and hardware, so measure it: render a representative section and scale up. Pick a section with the heaviest effects, or the estimate will run short.

Where

Timeline Duration
Length of the whole program(minutes)
Test Render Time
How long the test section took to render(minutes)
Test Section Length
Length of the test section(minutes)

Example: 60-minute program; a 2-minute test section takes 5 minutes to render

Calculation:
60 × (5 ÷ 2) = 150 minutes
Result:
About 2.5 hours (2.5× real time)
Storage Growth Rate
Daily Storage Need (GB) = Hours Shot × Bitrate (Mbps) × 3600 ÷ 8 ÷ 1,000

Storage per shooting day for one camera. Multiply by cameras and by the copies you keep.

Where

Hours Shot
Hours of footage per day(hours)
Bitrate
Recording bitrate(Mbps)

Example: 8 hours shooting at 100 Mbps

Calculation:
8 × 100 × 3600 ÷ 8 ÷ 1,000
Result:
360 GB per day
Upload Time Calculation
Upload Time (seconds) = (File Size × 8,000) ÷ (Upload Speed × 0.8)

1 GB is 8,000 megabits. The 0.8 allows for protocol overhead and a connection that rarely holds its rated speed; CineMath's Upload Time calculator shows a best-to-worst-case range instead of a single factor.

Where

File Size
Size of file to upload(GB)
Upload Speed
Internet upload speed(Mbps)
0.8
Overhead factor (20% reduction)(multiplier)

Example: 50 GB file, 100 Mbps upload

Calculation:
(50 × 8,000) ÷ (100 × 0.8) = 400,000 ÷ 80 = 5,000 seconds
Result:
About 83 minutes upload time

Case study

Multi-Camera Production Workflow

  • Corporate Video
  • Intermediate
  • Worked example

Scenario

A corporate event shot on 4 cameras for 6 hours, recording 100 Mbps long-GOP files, with an edited video due the same day.

Challenge

Estimate storage, proxy transcoding and upload time to see whether same-day delivery is realistic.

Solution

  1. Calculate storage at the recording bitrate
  2. Transcode proxies during the shoot as cards are offloaded
  3. Estimate the edit and color time
  4. Calculate the upload time for the finished file
  5. Leave time for a final QC pass

The numbers

  • Camera files: 4 cameras × 6 hours × 100 Mbps = 1,080 GB
  • 1080p ProRes Proxy at 29.97fps (45 Mbps): 4 × 6 hours × 45 Mbps = 486 GB, transcoded during the shoot
  • Upload: 10 GB × 8,000 ÷ (50 Mbps × 0.8) = 2,000 seconds, about 33 minutes
  • After wrap: 4 hours edit and color + 0.5 hours render + 0.6 hours upload + 0.5 hours QC ≈ 5.6 hours

Result

Same-day delivery works if proxies are made as cards come in, so editing can start when the shoot wraps rather than six hours later.

Key takeaways

  • Proxies of long-GOP footage are about playback, not space
  • Transcoding during the shoot takes proxy time off the critical path
  • Build QC and upload time into the schedule
  • Upload speed often becomes the bottleneck for same-day delivery

Calculators for this guide