JVET-AM0100 AHG9: Shutter interval information SEI message extension for rolling shutter cameras [L. Kerofsky, Y. He, S. Zhao, M. Karczewicz (Qualcomm)]

Extension of the shutter interval information SEI message is proposed to signal details of rolling shutter cameras. Rolling shutter cameras are commonly used in consumer, automotive and autonomous vehicle applications. When either the object or the camera exhibits fast motion, the image may be distorted by rolling shutter artefacts. It is asserted that these artefacts degrade many uses of such an imager in areas such as bifocal stereo, multi-sensor fusion or 3D scene reconstruction. Details of the subframe capture timing may be used to improve the performance of these applications. The extension includes the follow syntax elements to describe rolling shutter capture.

1. A syntax element, sii_rolling_shutter_scan_order, describes the direction of scan, top-to-bottom, bottom-to-top, left-to-right, or right-to-left.
2. A syntax element, sii_num_units_in_rolling_shutter_scan_interval, describes the duration of the scan in units already used in the SII message.
3. A syntax element, sii_num_units_in_rolling_shutter_scan_delay, describes the delay of the scan in units already used in the SII message.

The existing shutter interval SEI message assumes a global shutter.

It was noted that rolling shutter cameras are common, but often processing is often done to correct for that before doing video encoding. Some applications, such as depth estimation, may prefer to operate on content where rolling shutter correction had not been done.

Rolling Cameras typically roll top to bottom, but the camera may be rotated relative to the scene it is capturing.

It was questioned if the scan delay syntax element is needed.

It was questioned why the scan interval and delay are signalled for each temporal sublayer as it would be expected to be consistent.

There is some support for adding to the TuC.

Decision: Conditionally adopt to the TuC, subject to revised text being provided in a new version of the contribution that removes the scan delay syntax element and separate sublayer signalling of the scan interval.

Further discussed on 1 July 2025. Adoption confirmed.

JVET-AM0100 AHG9: Shutter interval information SEI message extension for rolling shutter cameras

Alpha channel info (ACI)