ProRes and DNxHR File Size per Minute (1080p and 4K)

How big is a minute of ProRes or DNxHR?#

A minute of ProRes 422 HQ at 1080p 29.97 fps takes 1.65 GB (220 Mbps x 60 / 8 / 1,000), and DNxHR HQ takes 1.56 GB (25.99 MB/s x 60 / 1,000). The lightest tiers need a fifth of that: 0.34 GB for ProRes 422 Proxy at 45 Mbps (Apple ProRes white paper) and 0.32 GB for DNxHR LB at 5.39 MB/s (Avid DNxHR specifications).

The size table lists gigabytes per minute for each tier that B-ROLL can write, at 1080p and UHD, 30p and 60p, with the vendor data rate in brackets. ProRes rates are the white paper’s 30p and 60p target rows, in Mbps. Each becomes GB as Mbps x 60 / 8 / 1,000. DNxHR rates come from Avid’s bandwidth page (29.97 and 59.94 fps, in megabytes per second), calculated as MB/s x 60 / 1,000.

Avid lists the same rate for DNxHR HQ and the 10-bit HQX, so one row covers both. For an hour, multiply by 60: UHD ProRes 422 HQ at 30p fills 398 GB (884 Mbps x 3,600 / 8 / 1,000), while UHD ProRes 422 Proxy fills 82 GB. What each tier is for sits in ProRes Proxy vs LT vs 422 vs HQ and DNxHR LB vs SQ vs HQ vs HQX.

How do you calculate file size from a data rate?#

File size in megabytes per minute equals the data rate in Mbps x 60 / 8. Sixty turns seconds into a minute, and 8 turns bits into bytes. Divide by 1,000 for gigabytes, or use the shortcut GB per minute = Mbps x 0.0075.

Two worked lines make the formula concrete. ProRes 422 HQ at 220 Mbps gives 220 x 60 / 8 = 1,650 MB, or 1.65 GB per minute. ProRes 422 Proxy at 45 Mbps gives 45 x 60 / 8 = 337.5 MB, or 0.34 GB per minute.

Avid publishes DNxHR in megabytes per second, not megabits, so skip the division by 8: DNxHR SQ at 17.21 MB/s x 60 = 1,032.6 MB per minute. To compare DNxHR with ProRes in Mbps, multiply Avid’s figure by 8, which puts DNxHR HQ at 207.9 Mbps (25.99 x 8) against 220 Mbps for ProRes 422 HQ.

Windows File Explorer reports sizes in binary units, where 1 GB means 1,073,741,824 bytes (1,024 x 1,024 x 1,024). A file of 1.65 billion bytes therefore shows as 1.54 GB in Explorer (1.65 x 10^9 / 1,073,741,824). Vendor tables and the figures on this reference use decimal gigabytes.

How do resolution and frame rate change ProRes and DNxHR file size?#

ProRes and DNxHR data rates scale almost linearly with pixels per second. UHD at 3840 x 2160 has four times the pixels of 1080p, and 60 fps stores twice the frames of 30 fps, so UHD at 60 fps needs roughly eight times the space of 1080p at 30 fps.

Apple’s own numbers show the pattern. ProRes 422 LT is 102 Mbps at 1080p 30p, 410 Mbps at 2160p 30p and 821 Mbps at 2160p 60p, ratios of 4.0 and 8.0. Avid’s DNxHR LB moves from 5.39 MB/s to 21.42 MB/s and 42.85 MB/s across the same steps.

B-ROLL keeps the source resolution and frame rate when it converts, so a 4K60 YouTube video becomes a 4K60 .mov. Look up the source’s own resolution and frame rate in the size table, not the resolution of your timeline.

How does a YouTube stream compare with ProRes and DNxHR?#

A YouTube stream is a small fraction of any ProRes or DNxHR tier at the same resolution, because VP9, AV1 and H.264 store most frames as differences from their neighbors. The exact gap depends on the bitrate of each upload, so measure the source before you plan.

B-ROLL shows the real bitrate of every downloaded file on its card, for example “Real bitrate 8.2 Mbps · 1080p”, measured on the file itself; the real bitrate and resolution of YouTube files explains the number. At 8.2 Mbps, one minute is 61.5 MB (8.2 x 60 / 8). The same minute as ProRes 422 LT is 765 MB, twelve times larger, and as ProRes 422 HQ it is 1,650 MB, 27 times larger.

The conversion adds no picture detail; it trades disk space for decoding cost. Ema Zamboni, who built B-ROLL, found 4K60 AV1 downloads heavy to play back in DaVinci Resolve on Windows 11, and AV1 or VP9 files sometimes crashed Resolve. That problem is why B-ROLL downloads YouTube videos in ProRes or DNxHR: the download finishes first, then ffmpeg converts it to a .mov.

How do you keep ProRes and DNxHR files small?#

ProRes and DNxHR files stay small when you convert fewer minutes at a lighter tier and a lower resolution. File size is minutes x GB per minute, so every lever cuts one of those two numbers.

• Let B-ROLL pick the tier. B-ROLL chooses the lightest ProRes or DNxHR tier that still preserves each source, and uses DNxHR HQX only for 10-bit sources. How B-ROLL picks a ProRes or DNxHR tier automatically shows the rule and its numbers.
• Download only the section you need. A clip download converts only the range between your start and end times: an 8-second UHD shot in ProRes 422 LT at 30p takes 0.41 GB (3.08 GB x 8 / 60), not the whole video.
• Cap the resolution. The Video quality menu offers 1080p, and a 1080p file needs a quarter of the UHD space in the size table.
• Choose videos, not whole playlists. The YouTube playlist and channel downloader lets you tick videos from a list or take only the latest few.
• Save audio only when you need just the sound; MP3, M4A, WAV, FLAC and OPUS skip the video conversion.
• Leave headroom during conversion. B-ROLL converts from an MKV master and deletes that master only after a successful conversion, so both files sit on the disk until the conversion ends.

For the choice between the two families, see ProRes vs DNxHR for editing; every codec page is collected under codecs and formats for editing YouTube footage.