HlsIntervalCadence
The cadence MediaConvert follows for generating thumbnails. If set to FOLLOW_IFRAME, MediaConvert generates thumbnails for each IDR frame in the output (matching the GOP cadence). If set to FOLLOW_CUSTOM, MediaConvert generates thumbnails according to the interval you specify in thumbnailInterval. If set to FOLLOW_SEGMENTATION, MediaConvert generates thumbnail playlist entries that align exactly with video segment boundaries. FOLLOW_SEGMENTATION requires 1x1 tiling.