Function push_video_header 

pub fn push_video_header(
    out: &mut Vec<u8>,
    codec: Codec,
    frame_type: u8,
    frame_id: u16,
    y_start: u16,
    width: u16,
    height: u16,
    reference: Reference,
)

Append the header of one encoded video frame or stripe: the tag, the codec and frame kind, then the frame id, the stripe’s top row, its width and height, and the id of the frame it predicts from, all big-endian u16. A frame that predicts from none, or whose encoder does not say, names itself there.