V4L2_BUF_FLAG_MAPPED
V4L2_BUF_FLAG_QUEUED
V4L2_BUF_FLAG_DONE
V4L2_BUF_FLAG_KEYFRAME
V4L2_BUF_FLAG_PFRAME
V4L2_BUF_FLAG_BFRAME
V4L2_BUF_FLAG_TIMECODE
V4L2_BUF_FLAG_INPUT