Does log video use more storage?
Log video can use more storage when a grading workflow uses a higher-data-rate codec or bitrate. The log curve itself does not increase the encoder's data rate. Codec, bit depth, frame size, frame rate, and bitrate determine how fast storage fills. Log Cam: RAW 4K Video Camera lets you choose codec and bitrate when recording. 1,2,3
Key takeaways
- Log video often uses more storage because codec, bit-depth, and bitrate choices for grading can demand higher data rates.
- The log curve itself does not increase ProRes data rate. Apple names codec, frame size, and frame rate as primary factors.
- Bit depth matters because log encodings need enough code values to preserve tonal precision for grading.
- Codec choice changes storage dramatically because Apple’s 4K ProRes formats show very different hourly sizes at the same frame rate.
- Duration multiplies every data-rate choice, so long interviews, ceremonies, and repeated music-video setups make storage differences obvious.
- When internal storage is tight, pick a lower-bitrate HEVC preset or record directly to an external drive.
Long recordings and repeated takes fill storage
Total file size grows with recording time. A day of long clips and repeated takes can exceed available space even when a short test clip fits.
Recording days that need more storage
- An afternoon wedding with the ceremony, speeches, and long moments between cuts.
- A phone with two years of camera roll and little free space left.
- A sit-down interview that runs for forty minutes without a break.
- A music video where the crew repeats each setup three or four times.
Codec and frame settings set the ProRes data rate
The log curve is not one of Apple’s primary ProRes data-rate factors. Apple states, “The data rate of a ProRes format is determined primarily by three key factors: ProRes codec type, encoded frame size, and frame rate.” The curve changes tonal encoding, while the encoder still follows the chosen format and frame settings.1
The same log profile can be recorded in different formats, each with its own data rate. The curve maps exposure values into code values before the encoder writes the stream, so storage follows the codec and settings you pick.1,3
Bit depth in log formats
Log workflows also depend on quantization precision because grading needs smooth tonal steps. ARRI’s LogC4 specification gives a concrete example: it optimized LogC4 for 12-bit encoding to gain precision at each stop versus 10-bit LogC3. That does not make every log format 12-bit. It shows that a log design can carry a real bit-depth floor.3
The app records ProRes or 10-bit HEVC, so the chosen format carries the log signal into storage. A wider code space does not mean the curve itself creates extra bytes. It means bit depth is part of the format choice you make before any storage math. Codec and bitrate then decide how fast each clip grows.3
Codec and bitrate change storage by a wide margin
Clip size depends on format, bitrate, and recording time. Apple’s table gives the ProRes figures below. The HEVC rows use the app’s 30 to 500 Mbps presets with the same conversion convention as Apple’s appendix. The lowest HEVC preset is 13.5 GB per hour, while ProRes 422 HQ is 398 GB. The highest HEVC preset, 500 Mb/s, is larger than ProRes 422 LT.1
| Codec | Data rate | One hour |
|---|---|---|
| ProRes 422 HQ | 884 Mb/s | 398 GB |
| ProRes 422 | 589 Mb/s | 265 GB |
| ProRes 422 LT | 410 Mb/s | 185 GB |
| 10-bit HEVC, highest preset | 500 Mb/s | 225 GB |
| 10-bit HEVC, lowest preset | 30 Mb/s | 13.5 GB |
A full phone does not make log impractical
If internal storage is tight, pick HEVC with a lower bitrate and keep the same log profile. The app offers several HEVC bitrate presets.
When internal storage is the limit, record to an external SSD or hard drive connected to the phone. The app can use that drive as the recording destination, so clips land there instead of internal storage.
Frequently asked questions
- Does the log curve itself make clips larger?
- No, the curve itself does not set ProRes data rate. Apple names codec type, encoded frame size, and frame rate as the primary factors. The curve changes tonal encoding, while those format choices control the target stream. 1,3
- How much storage does one hour of 4K ProRes use?
- At 30 fps and 3840 x 2160, Apple lists 398 GB per hour for ProRes 422 HQ. It lists 265 GB for ProRes 422 and 185 GB for ProRes 422 LT. Apple also says actual ProRes data rate usually stays close to the target. 1
- Does HEVC use less storage than ProRes?
- Usually. Apple says ProRes files can be up to 30 times larger than HEVC files. The exception is the highest HEVC preset: at 4K and 30 fps, 500 Mb/s comes to about 225 GB per hour, more than ProRes 422 LT at 185 GB. Codec and bitrate matter more than the log curve when storage is the concern. 2
Sources
- 1.Apple Inc., “Apple ProRes White Paper,” apple.com
- 2.Apple Inc., “About Apple ProRes on iPhone,” support.apple.com
- 3.ARRI, “ARRI LogC4 Logarithmic Color Space Specification,” arri.com