Sources and Method
Every number this site uses, where it came from, and how it was checked. If a figure is not on this page, it is not in the calculators.
The unit policy, stated first because it changes every answer
A calculator that does not tell you which gigabyte it means can be wrong by seven percent without anybody noticing. This site uses decimal units throughout:
- 1 Mbps is 1,000,000 bits per second
- 1 MB is 1,000,000 bytes, 1 GB is 1,000,000,000 bytes, 1 TB is 1,000,000,000,000 bytes
- Binary units are offered separately and named honestly as GiB and TiB, where 1 GiB is 1,073,741,824 bytes
This is not an arbitrary choice. Card and drive makers label capacity in decimal units, so the number printed on the card is a decimal number. Apple's ProRes white paper prints a gigabytes per hour column that only reconciles with its megabits per second column in decimal units. Blackmagic's own data rate calculator says a 1 TB drive holds 1.2 hours at 235 MB/s, which is only true if a terabyte is a thousand billion bytes. Three independent publishers, one convention, so this site follows it.
A 128 GB card therefore shows as about 119.2 GiB in an operating system that divides by 1024 and still writes GB. Nothing is missing. It is the same 128,000,000,000 bytes described in different units.
Primary sources
Apple, ProRes target data rates
Document dated April 2022. Read for this site on 22 August 2026, from the PDF rather than from a copy of it.
Apple ProRes white paper, April 2022, document 028-00500-A. The appendix titled Target Data Rates on pages 19 to 21 lists every supported frame size and frame rate against the six ProRes codecs, in megabits per second and in gigabytes per hour.
How it was used. All 58 rows were machine read from the PDF rather than retyped, giving 348 data rate values, and they are shipped in full. The ProRes calculator and the ProRes options in the storage calculator read from that table and nothing else. Where Apple publishes no figure for a combination, the tool returns nothing rather than interpolating.
How it was checked. Apple prints both columns, so the table can be verified against itself: megabits per second, multiplied by 3600 and divided by eight, has to give Apple's own gigabytes per hour. Across all 348 cells it does, with a worst case difference of 0.7 GB per hour, which is Apple rounding each column independently. That check runs in the test suite.
Blackmagic Design, Blackmagic RAW
Blackmagic publishes no date on either page. Both read for this site on 22 August 2026.
Two sources, used for two different things.
The Blackmagic Cinema Camera manual is the source for the definition. It explains that the constant bitrate settings 3:1, 5:1, 8:1 and 12:1 are ratios between the uncompressed RAW file size and the recorded file, and gives the example that 12:1 compression produces a file roughly twelve times smaller than uncompressed RAW. It also explains that constant quality settings Q0 to Q5 have no predictable file size, and notes that on camera the Q0 estimate resembles 3:1 and the Q5 estimate resembles 12:1.
The Blackmagic RAW data rate calculator on the product page is the source for the check. Read on 22 August 2026 for the Blackmagic Cinema Camera at 24 fps, it gives 6K DCI at 235 MB/s for 3:1, 141 for 5:1, 88.4 for 8:1 and 59.0 for 12:1, and 4K DCI at 108 MB/s for 3:1.
What is derived. Blackmagic does not publish a table of data rates, so this site computes them from their published ratio: width times height times bits per photosite times frame rate, divided by the ratio. Twelve bits per photosite is the assumption, and it appears on the BRAW page as an input you can change rather than as a constant hidden in the code.
How it was checked. Against those five published figures. The derivation lands within 1.7 percent on every one, in both directions, and the ratio scaling is exact. The comparison is printed on the BRAW page itself and is repeated in the test suite.
GoPro, HERO13 Black capacity chart
Article dated 04/09/2024 by GoPro. Read for this site on 22 August 2026.
GoPro Support, HERO13 Black SD card capacity in various settings, dated 04/09/2024. It lists recording time per resolution, frame rate and aspect ratio on a 128 GB card at both the high and standard bit rate settings, and states that you can multiply or divide the time relative to your own card size.
How it was used. The chart is shipped unmodified and scaled linearly, which is the method GoPro recommends. The implied data rate shown alongside is arithmetic on GoPro's numbers, not a GoPro published rate, and every page that shows it says so.
The caveat GoPro states. These are estimates in a static environment, and the HERO13 Black bit rate is highly variable with scene complexity. GoPro also notes that older models held a consistent bit rate at each setting and that this changed with the newer encoder.
YouTube, recommended upload encoding settings
Google publishes no date on this help page. Read for this site on 22 August 2026.
YouTube Help, recommended upload encoding settings. Source of the standard dynamic range and high dynamic range video bitrate tables and the audio bitrate recommendations of 128 kbps mono, 384 kbps stereo and 512 kbps for 5.1.
How it was used. Copied exactly, ranges kept as ranges. Where YouTube publishes 35 to 45 Mbps, this site offers 35 to 45 Mbps and shows a range of answers rather than inventing a midpoint and calling it official.
Vimeo, compression guidelines
Vimeo publishes no date on this help page. Read for this site on 22 August 2026.
Vimeo Help Center, video and audio compression guidelines. Source of the bitrate ranges by resolution and the audio recommendation of 320 kbps at 48 kHz.
Instagram, reel requirements
Instagram publishes no date on this help page. Read for this site on 22 August 2026, and read again for what it still does not say.
Instagram Help Center, reel size and aspect ratios. Cited on this site for what it does not contain. Instagram publishes an aspect ratio range, a minimum frame rate of 30, a minimum resolution of 720 pixels and codec requirements. It publishes no target bitrate, so this site offers none.
SD Association, card capacity standards
The SD Association publishes no date on this overview. Read for this site on 22 August 2026.
SD Association, capacity overview. Source of the standard boundaries used on the capacity pages: SD up to 2 GB with FAT12 or FAT16, SDHC over 2 GB to 32 GB with FAT32, SDXC over 32 GB to 2 TB with exFAT, and SDUC over 2 TB to 128 TB with exFAT.
SMPTE ST 12-1, timecode
The standard itself is a paid document and was not read directly. The public behaviour it defines was checked against this calculator on 22 August 2026, and that check runs in the test suite.
The drop frame rule implemented by the timecode calculator is the standard one: two frame labels are skipped at the start of every minute except every tenth minute, at 29.97 fps, and four at 59.94. This is defined by SMPTE ST 12-1, which is a paid standard and is therefore cited rather than quoted. The behaviour it produces is publicly checkable and this site checks it: the label after 00:00:59;29 is 00:01:00;02, one hour of drop frame timecode is 107,892 frames, and 108,000 frames of 29.97 reads as 01:00:03;18.
What is computed rather than cited
Three things on this site are arithmetic rather than quotation, and all three are labelled where they appear:
- Blackmagic RAW rates, derived from the published ratio as described above.
- GoPro implied data rates, derived from GoPro's own published recording times on a 128 GB card.
- Uncompressed PCM audio rates, which are sample rate times bit depth times channels. 48 kHz, 24 bit, stereo is 2,304 kbps, and that is a definition rather than an opinion.
What this site refuses to publish
There is no table of camera models with bitrates on this site, because manufacturers rarely publish that data and the tables you find elsewhere are mostly copied from each other. There is no Instagram recommended bitrate. There is no constant quality BRAW file size. Where a figure does not exist, the honest answer is that it does not exist, followed by the fastest way to measure it yourself: record ten seconds, divide the megabytes by the seconds, multiply by eight.
The test suite
The calculation engine is covered by tests that run with a single command and no dependencies. They check, among other things:
- That our gigabytes per hour reproduces Apple's own column across all 348 cells.
- That the Blackmagic RAW derivation lands within two percent of Blackmagic's five published figures, and that the ratios scale exactly.
- That timecode survives more than three thousand round trips across every supported rate, drop frame included, and that labels drop frame never writes are rejected instead of being silently moved.
- That 180 degrees at 24 fps is 1/48, that 172.8 degrees at 24 fps is exactly 1/50, and that an impossible shutter is refused rather than displayed.
- That no hostile input, empty, negative, textual, absurd or infinite, can produce NaN or undefined anywhere in the interface.
Corrections
If a manufacturer publication disagrees with anything here, the publication wins. Send it to ulisses@openyourais.com and the page will be corrected.