How to choose the error concealment method for openh264?

Question

What does these error concealment enum means for openh264? Are there any documentation for them?

 typedef enum {
      ERROR_CON_DISABLE = 0,
      ERROR_CON_FRAME_COPY,
      ERROR_CON_SLICE_COPY,
      ERROR_CON_FRAME_COPY_CROSS_IDR,
      ERROR_CON_SLICE_COPY_CROSS_IDR,
      ERROR_CON_SLICE_COPY_CROSS_IDR_FREEZE_RES_CHANGE,
      ERROR_CON_SLICE_MV_COPY_CROSS_IDR,
      ERROR_CON_SLICE_MV_COPY_CROSS_IDR_FREEZE_RES_CHANGE
    } ERROR_CON_IDC;