ED cameras record videos in the StereoLabs SVO2 format (.svo2 file extension), introduced with ZED SDK 4.1 and used by default since then. Legacy .svo files are still supported for playback.
The final file size depends on four main factors: resolution, frame rate, compression mode, and, for H.264/H.265, the encoding bitrate.
Compression modes
The ZED SDK provides both lossless and lossy compression modes:
| Compression Mode | Average Size (% of RAW) |
|---|---|
| LOSSLESS (PNG/ZSTD) | 42% |
| H.264 (AVCHD) | 1% |
| H.265 (HEVC) | 1% |
| H.264 LOSSLESS | 25% |
| H.265 LOSSLESS | 25% |
H.264 and H.265 modes use the NVIDIA hardware encoder (NVENC), so they are the recommended choice for long recordings: the file size is drastically reduced and the CPU/GPU load remains minimal.
Typical file sizes
As a reference, for a recording at HD2K@15Hz (ZED, ZED Mini, ZED 2i):
- LOSSLESS: about 180 GB per hour
- H.264/H.265 at the default bitrate: about 7 GB per hour
When using H.264 or H.265, you can change the bitrate through the RecordingParameters of the API; the bitrate directly determines the file size and the video quality.
The data rate is roughly constant across resolution/frame rate combinations with the same pixel throughput (for example, HD2K@15Hz is comparable to HD720@60Hz). Recording at a lower resolution and frame rate, such as HD720@15Hz, proportionally reduces the file size.
The same considerations apply to the GMSL2 cameras (ZED X, ZED X Mini, ZED X One) at their native resolutions (HD1200, HD1080, SVGA).
Note: SVO2 files store not only the stereo video stream, but also timestamps, high-frequency IMU/sensor data, and optional user custom data. The sensor data contribution to the total file size is negligible compared to the video stream.
For more information, see the Video Recording documentation.