Multiply your camera's bit rate in megabits per second by 0.45 and you have gigabytes per hour. A Sony FX3 recording XAVC S-I 4K at 23.98p runs at 240 Mbps, about 108 GB an hour; XAVC HS 4K at 100 Mbps comes to about 45 GB. Two cameras rolling three hours each in the intra format is about 650 GB for one wedding, before audio, proxies or a single backup copy, and three copies of a 30-wedding season at that rate is about 58 TB. Work it out from your own settings with the method below, and budget 15 to 40% more than the arithmetic, because cameras record at a variable bit rate.
The bit rates come from Sony's Help Guide for the ILME-FX3, and the audio figures from the sample rate and bit depth. The arithmetic, the example wedding days and the season totals are ours, so swap in your own camera, settings and hours.
The arithmetic
A bit rate of 1 Mbps is a million bits a second. An hour has 3,600 seconds and a byte has 8 bits, so one hour at 1 Mbps is 450 million bytes, 0.45 GB. Every figure below is that multiplication, using the decimal gigabytes that memory cards and drives are sold in.
What each FX3 format takes
The FX3's Record Setting tables list these 4K options, among others. Gigabytes per hour are ours:
- XAVC S-I 4K (intraframe, 4:2:2 10-bit): 240 Mbps at 23.98p, about 108 GB an hour; 300 Mbps at 29.97p, about 135 GB; 600 Mbps at 59.94p, about 270 GB.
- XAVC HS 4K (H.265, Long GOP): 100, 50 or 30 Mbps at 23.98p, about 45, 22.5 or 13.5 GB an hour; up to 200 Mbps at 59.94p, about 90 GB.
- XAVC S 4K (H.264, Long GOP): 100 or 60 Mbps at 23.98p, about 45 or 27 GB an hour; 140 Mbps at 29.97p, about 63 GB.
- Proxies, if you record them alongside: 16, 9 or 6 Mbps HD, about 7.2, 4 or 2.7 GB an hour on top.
At 24p, the intra format is 2.4 times the size of 100 Mbps XAVC HS. Whether that size buys you smoother editing depends on your computer and your editor; how the free version of DaVinci Resolve handles the FX3's H.264 and H.265 files is covered in Resolve Studio against Premiere.
Why Sony's own table runs higher
The same guide has a table of approximate recording times by card. Read against a 128 GB SD card, it implies more than the arithmetic does: 1 hour 35 minutes of XAVC HS 4K at 59.94p and 150 Mbps works out to about 81 GB an hour, against 67.5 GB by multiplication, and 25 minutes of XAVC S-I 4K at 600 Mbps to about 307 GB an hour, against 270. Across the rows we checked, Sony's table runs 14% to 40% above the arithmetic, with the gap widest at the lower bit rates.
Sony gives the reason in a note under the table: the camera uses a variable bit rate that adjusts to the scene, so a fast-moving subject takes more memory and shortens the recording time. A dance floor is a fast-moving subject. Plan cards from Sony's table, which is the conservative figure, and treat the arithmetic as the floor.
What the audio adds
Uncompressed audio is easy to work out exactly. A 32-bit float file at 48 kHz stores 4 bytes for each of 48,000 samples a second, 192,000 bytes a second per channel, which is about 0.69 GB an hour. At 24-bit it is about 0.52 GB. Zoom's claim that a 1 TB card holds over 180 hours on the F3 at its highest setting checks out on the same arithmetic: two channels of 32-bit float at 192 kHz is about 5.5 GB an hour.
So audio is the small part. Four mono 32-bit float recorders running for eight hours come to about 22 GB, a few percent of a two-camera 4K day.
Three example wedding days
With two cameras rolling three hours each, an assumption to replace with your own coverage:
- XAVC S-I 4K at 23.98p (240 Mbps): about 648 GB.
- XAVC HS 4K at 23.98p and 100 Mbps: about 270 GB.
- XAVC HS 4K at 23.98p and 50 Mbps: about 135 GB.
Add the audio, proxies if you record them, and 15 to 40% for the variable bit rate, and you have the size of one copy of one wedding. A ceremony you cannot restart also sets the card: at 600 Mbps a 128 GB SD card holds about 25 minutes on Sony's table, which is shorter than a long ceremony. A card that fails halfway through is a different problem, and what its warranty covers is in the memory card warranty post.
A season, with three copies
Thirty weddings at 648 GB is about 19.4 TB of camera originals. A 3-2-1 backup keeps three copies, which takes that to about 58 TB. At 270 GB a wedding, the same season is 8.1 TB, or 24.3 TB with three copies. The bit rate you choose in the menu is the biggest storage decision you make all year, and it is made one wedding at a time.
How long those copies have to stay on the drives is the other half of the bill. That is set by your contract and by limitation periods, which are covered in how long to keep wedding files.
Where Pixally Prep fits
If you prep your footage with Pixally Prep, the size of the day also sets how long it takes. Its guide figure on a Mac is about 45 seconds for each GB, about 2 hours for 160 GB, so the 648 GB day above is about eight hours and the 270 GB day about three and a half. While a wedding prepares, it needs about 25 GB of free space and about 3 GB free on the footage drive for the project, and its timelines point at your files where they are, with no need to upload them anywhere. The first wedding is free, one per person and one per computer, and each one after that is $8.99.
Common questions
- How many GB is a wedding video shoot?
- It depends on the bit rate and how long the cameras roll. Gigabytes per hour is the bit rate in megabits per second times 0.45, so two cameras rolling three hours each at 240 Mbps is about 648 GB, at 100 Mbps about 270 GB, and at 50 Mbps about 135 GB, before audio, proxies or any backup copy.
- How much storage does a wedding videographer need for a year?
- Camera originals for one wedding, times weddings in a season, times the copies you keep. Thirty weddings at 270 GB is 8.1 TB, or 24.3 TB with the three copies a 3-2-1 backup keeps. At 648 GB a wedding it is about 19.4 TB, or 58 TB with three copies.
- How many GB per hour is 4K video?
- The bit rate in megabits per second times 0.45. On a Sony FX3, XAVC S-I 4K at 23.98p records at 240 Mbps, about 108 GB an hour, and XAVC HS 4K at 100 Mbps comes to about 45 GB. Sony's own recording-time table runs higher than the arithmetic, because the camera records at a variable bit rate.
- How much space does 32-bit float audio take?
- About 0.69 GB an hour per channel at 48 kHz: four bytes a sample, 48,000 samples a second. Two channels at 192 kHz come to about 5.5 GB an hour, which is why Zoom can say a 1 TB card holds over 180 hours on the F3 at its highest setting.
- What size memory card do I need to film a wedding ceremony?
- One that holds the whole ceremony at your settings, with room to spare. Sony's table for the FX3 puts about 1 hour 35 minutes of XAVC HS 4K at 59.94p and 150 Mbps on a 128 GB SD card, and only 25 minutes of the 600 Mbps intra format. Check your own camera's table, and never plan to change cards during the vows.
