fn read_mdhd()

in mp4parse/src/lib.rs [4616:4655]
28 lines of code
2 McCabe index (conditional complexity)

fn read_mdhd<T: Read>(src: &mut BMFFBox<T>) -> Result<MediaHeaderBox> {
    let (version, _) = read_fullbox_extra(src)?;
    let (timescale, duration) = match version {
        1 => {
            // Skip 64-bit creation and modification times.
            skip(src, 16)?;

            // 64 bit duration.
            (be_u32(src)?, be_u64(src)?)
        }
        0 => {
            // Skip 32-bit creation and modification times.
            skip(src, 8)?;

            // 32 bit duration.
            let timescale = be_u32(src)?;
            let duration = {
                // Since we convert the 32-bit duration to 64-bit by
                // upcasting, we need to preserve the special all-1s
                // ("unknown") case by hand.
                let d = be_u32(src)?;
                if d == u32::MAX {
                    u64::MAX
                } else {
                    u64::from(d)
                }
            };
            (timescale, duration)
        }
        _ => return Status::MdhdBadVersion.into(),
    };

    // Skip uninteresting fields.
    skip(src, 4)?;

    Ok(MediaHeaderBox {
        timescale,
        duration,
    })
}